400 ft. lbs. fo cheap

Here's a couple of questions for you 350 guru's out there:

The 'magic' number for torque output on a Buick 350 seems to be around 400 pounds. My question is can it be done with low compression running on regular grade fuel with stock manifolds and a smooth idle? (extra work considered, of course, such as port work and possibly a lopier idle)

Question number 2: how big of a cam can you go before it starts to affect idle quality, i.e., begins to have a noticable lope? I presume it's safe to assume that the TA rv-12 has a smooth idle in a 350, but what about the TA 112? The TA 212 has a slight lope from what I've read, but I don't see much about the TA 112 in a 350. I know it idles smoothly in a 455, but what happens when you take away 105 cubes?o No:

Keeping static comp between 8:1 and 8.5:1 while improving air flow and not bringing DCR up to the point where you need better than regular grade gas, while getting as close to or over 400 ft. lbs. is the goal.

 

Embrace compression. :Smarty: Optimize your static & dynamic compression. That is where your torque will come from.

One of the problems with these old motors is that they don't have the volumetric efficiency that new motors do. So, you have to maximize the energy potential of what you can get into the cylinder. This is done by squeezing it as hard as possible.

Fortunately, you do not need a PHD in engine theory to achieve this. You can just use others practical experience and it will get you to the same place. If you get that motor to around 9.5:1 and use a camshaft from an experienced Buick expert that is designed to operate in the 1000-5000 range, you will be on your way to getting the torque you want. Most likely something in the 205 to 212 degrees at .050" intake duration ought to do it.

Now, if you really want to make some midrange torque, a modern designed roller cam would make a substantial improvement, but then you are hitting the wallet pretty hard.

 

I am doing this very project you are asking about right now for my nieces car. exceptions are static comp is 9.2 and I am running a lunati voodoo cam 250/256 advertised duration. so I can capitalize on the 350's long stroke for torque. it is all in the details as to how you get there.

 

This might be of some value to you..

http://www.v8buick.com/showthread.p...erence-between-these-two-cams-I-want-to-learn

 

____________
Thanks fellas!

I'm well aware of the power potential of a 9.5 comp engine, and reaching 400 ft. lbs. in one of those is pretty easy to do. Didn't know if anyone has done it, or if it's possible, with a low comp 350 and a smooth idle. Magic 8 ball says: outlook not so good

The '71 v4 stocker claims 360 ft. lbs., so with some mild port work and a high lift, low duration cam you might see what, 380 or 390 tops? I was really hoping to get away with regular gas without having to stuff a low comp 455 under the hood, and 400 ft. lbs. is really the minimum amount I would be satisfied with, yet 450 ft. lbs. from a stock 8:1 455 is really too much for what I want.

Hoping for 410-430 ft. lbs., and a 9.5 350 looks to be about the only way to get there with the array of Buick engine builds available. Perhaps a low comp 400 or 430 would do it, but there is no such beast without custom parts. (unless the 400 heads on a 430 would do it--aren't those 78cc chambers?)

or going with a castrated '75-'76 455, which I don't want.

Looks like I'm going to have to open up the little book of tricks and shave off bits of friction here and there to get it.

Anyone know much about the TA 112 cam? Smooth idle or slight lope? It's probably going to be in-between if I had to guess. Might lope a little when cold with a low rpm idle, and smooth up when warm and a 650-700 rpm idle maybe. Be nice to hear from someone out there who's actually used the TA 112 in a 350.

Specs on it are (with 1.55 rocker ratio) .455 lift intake, .468 lift exhaust; 210* intake, 215* exhaust @.050" with 110* lobe center. In a 455 it's smooth, (more cubes handles more duration, plus for 455 it has 112 LS) but I'm thinking for a 350, it might be borderline. The TA RV-12 should be smooth(er) with .440 lift and 205* duration @.050", exhaust and lobe center same as TA 112.

Really didn't want to go with the TA 212, though I know it's a good one, because I'm looking for more low-mid torque output. Even if actual peak torque numbers are the same or similar, I'd like it at a lower rpm since I'll be using one of those cross-country gears (non-posi). Goal here is smooth idle and 400+ ft.lbs.


Thanks for all the great input guys, this place is awesome.

 

If you run pistons that will give it quench,then you could run 9 to 9.5:1 static,and a mild roller cam,some head porting,and intake porting you should be right there. Its not rocket science,seems very doable,with some Flat Head Ford after market rods,and a piston like this;

http://www.summitracing.com/parts/slp-h850cp/overview/

You'll have to special order them with .750" wrist pins,and locks for floating pins.Or make some insert sleves for the pistons,depending on your skills,or your skilled connections.

heres a link for the rods;

http://www.ebay.com/itm/New-Flathea...Parts_Accessories&hash=item2ec6238d0b&vxp=mtr

 

Speaking of which, instead of using a larger cam to get air flow, why not use one with smaller, safer, more efficient lobes and instead do some port work on the iron? More work, but better results. Increasing velocity for low-mid range applications would be the answer, I'm thinking.

With most of the 350 benchmarks I've seen on head flow (from stock, untouched, to moderately ported), it seems the heads are limited to about .500 lift, and after that, the numbers plane off and don't increase by much. In fact, I think .450-.475 is probably the optimum lift on pretty much any port job, unless you go radical with the porting. Cam duration is where the power's at, but there's a sweet spot you have to find that matches your port work and drivability goals. (My goal is to retain a smooth idle, but I'm having my doubts this will be realistic)

Flow seems to favor the exhaust in terms of lift, meaning, more lift on the exhaust side. So any cam with ~.425-.450 lift on intake, and add about .025 to that on exhaust, like ~.450-.475. The TA RV-12, TA 112, and TA 212 seem to be ideal cams for mild-moderate combinations.

But which one?

Perhaps none: I'm thinking of a custom cam for the 350 that could capitalize on adding more duration, but having a wider lobe separation for a smooth idle, I just need input on the spec from people who are into this same idea.

Sound interesting?

Most people want that nice lopey sound, but I'm an old man I guess and want to retain stealth, both visually and audibly. Smooth idle and quiet mufflers, anyone?

---------- Post added at 06:10 PM ---------- Previous post was at 05:36 PM ----------

What's your take on using hypereutectic pistons? I've heard good and bad. TA strongly recommends steering clear of them.

Idea here is 'fo cheap' though, so custom parts kinda goes against that idea. I.E., using mostly stock rotating assembly with better main and rod bolts. Which reminds me, what's your opinion on using the studs/nuts on '68-'72 vs the bolts on '73+ rods? Seems to me the bolts would be better, since all aftermarket forged rods use this concept. Undercut radius would provide better clamping force, I would think.

Which would make the stock '73+ rod 350's more durable than the stud/nut design on all stock big blocks too, correct?

Also, being able to get away with regular grade fuel would be a definite bonus. Maybe use 10:1 cast dish pistons with thicker head gasket and extra polish work on the combustion chamber to eliminate hot spots? Might end up with 9:1-9.25:1 and still use regular.

 

Hypereutectic pistons should be fine for what your trying to do,I have ran them in other engines without a problem. Your not building a race engine after all,if you wanted to spin it to 7,000+ with a high HP application on a regular basis,then yeah,you're going to want forged.

Yeah,thats one of the problems with Buick engines,not much after market support,not very many piston choices.And with the Buick 350 open combustion chamber,its hard to get that "quench" effect that helps an engine not detonate(spark knock)with the available pistons for it. And yet another challenge for building a ssb 350 is the very tall deck height for a small block,with rods that should be longer.(a sbb 350 has a taller deck height than a bbc 10.188" vs 9.80",with the tall deck bbc only being slightly taller at 10.200")

Sean has dynoed engines with the 2 different rods to find out what the fail limit is for them,and I think the earlier rods failed at around 400 HP,and the later rods were good to(if memory serves me right)around 600 HP. The male rods with nuts(LOL) are weaker because the trough hole is a larger diameter than the threaded hole.I think Sean said that they break along the side where the bolt(stud) goes through the rod where it is thin.
And to prep the later rods to handle more HP,they need a lot of work,like polishing the beams,among other thing,a search on here will give you the details. Then the cost of making the later stock rod handle the HP depends on what your machine shop charges to recon them,and the cost of the good ARP bolts. Around $20 a rod to recon,and $120 for ARP bolts,thats around $280 and a lot of work to make the 73-81 rods good enough to run in high HP engine.,and they will still be heavy cast rods.But for what you want to do,a lot of the prep work can be skipped,but ARP,and reconditiong would be a good idea.

And like I said about "quench" that would help you get away with running reg.gas with 9.5:1 compression,with a cam that will give you 7.8 to 8:1 DCR.The extra static/dynamic compression with good quench will give better mpg too.

I am runnig hypereutectic pistons in my sbc 383,with 9.9:1 compression,and it runs fine on 87 octane,but it has aluminum heads,so 9.5 would be the max for cast iron heads if the engine is setup right.

I hope this helps.

:beer

Derek

 

Ok scrap the low comp idea. lol

Sounds like I'm going to have to shave a bit off the deck and heads along with a thinner head gasket to optimize the quench. Do you suppose the increased quench would offset the possibility of detonation from the increased compression from the shaving, or would I want to stick with a .040" composite head gasket?

How high can you push DCR before it detonates on premium? Getting DCR low enough to run regular will have the opposite effect that I'm looking for: more torque. I suppose if you were to widen the LSA, increase DCR and quench, and install the cam at more advance, it might start to look like where I want to be.

I need to give this some more thought.

Thanks a ton for your input, it's really helping.

 

For the very smooth idle that you are looking for, keep the overlap around -15 degrees or less.
Speading the cam LSA to decrease overlap will work but it also moves the torque higher in rpm.
You didn't say if you were looking for low end torque?

You pretty much have the rest figured out.
The better the quench the higher the DCR can be. With good quench and a smooth combustion chamber, 8:1 DCR is good limit for premium gas using iron heads.
With piston to cylinder head clearances above .040" and if you want some margin, a DCR closer to the mid 7s would be better.

Torque equates more with cylinder fill or VE. Since you want to limit the cam size for the sake of idle quality, you are left with port work to accomplish better VE.

Ideal case would be to have a piston that has a dome that fits into the open chamber with a stepped dish design that has enough volume for a 9.5:1 compression ratio. It would look similar to this.

The quench distance would be the head gasket thickness. AM&P can supply such a piston.
Have the pistons made to fit the Callies Compstar 6.440 LS "H" beam rod. CSC6440CS2A2AH $550

Do some port work and use the TA 112 on a 113 to 114 LSA.
The DCR would be around 7.8 with a 9.5 Static compression ratio.

The only problem is you said "fo cheap"

Paul

 

Now your talking. I have thought this piston design would be a great idea for the SBB for a while now. Might have to check or machine the combustion chambers of the heads just to assure no interference, but if done correctly this would be sweet.

 

Agreed, although I ran kenne-bell hyper pistons in my stock-block/manifolds, "built-as-a-70-gs350-with-10.2CR" engine, and in my 150k-mile experience I could run good brand-name mid-grade gas no problem without pinging, as long as I kept the ignition advance in check. Which became a balancing act, since it REALLY liked a lot of advance everywhere except full throttle, soo much soo that iirc I ended up with almost no vacuum advance since there was soo much initial and mechanical. Sounds odd, but that's where I ended up with it after trying lots of advance-curve tweaking.

As far as hypers standing up to detonation, mine did an apparently GREAT job - I tended to run mine on the bleeding edge of too much advance, and several times when towing the boat on hot days Id basically have to drive it on/off the edge, with crossed fingers that it wasn't going to ping itself apart.

 

Zero the deck. keep the composite head gasket, mill the heads accordingly to achieve optimum DCR for your cam of choice. capitalize on the stroke of the 350 by keeping duration small... ie TA RV12, Lunati Voodoo 1092070.

remember the wider the LSA the smoother the idle, better vacuum and broader torque curve.
do some mild head work and port match intake. use all stock parts for rotating assembly no need to waste money on pistons. stock low comp pistons work great. upgrade to 73 rods with ARP kit.
good tune.

head work to match the cam makes a big difference!
small tube headers will really wake up this combo more!

 

I want to thank everyone in this thread for participating and giving great advice and information. You guys are awesome.

 

Supposing I were to put this very engine into a G body Regal, my transmission choice would be an st300 (this is not a 'set in stone' decision, just my ideal), and keeping the peg-leg axle under it. Those are 7.5's, correct? ratio will probably be 2.73 or 3.08, which is what I'd want. I know these axles aren't durable beyond a certain point, but I'd sure hate to be away from home and it go out on me. I'm thinking with the st300 less strain will be placed on the 7.5 in terms of sudden jolts, which will help ensure it holds together.

Would it be worth upgrading to another axle type, say the 8.5? and how big of a pain would this upgrade be, should it be necessary?

I used to have a 350cid/st300 setup in a couple of '68's and I really liked the dynamics of that combination. My main goal is to have some nice power, decent mileage (ideally regular gas, but if not, that's ok), and burnout every now and then without fearing breaking something.

On a side note, I've often pondered the mystery that is the Buick 350. I advanced the timing on both my 350's, yet one was a 2v and the other a 4v. What I noticed was both would run fine on Ammoco 93 with advanced timing, and fine on 89 leaded when timing was set normal. (This was back in the late 80's when leaded fuel was still around, and the 93 was fairly new)

The 2v is supposed to have 9:1 but the 4v is supposed to have 10.25. Felt to me like it had the same comp as the 2v engine. Both engines ran great, and I got a lot of comments and compliments on them from those who scarcely knew Buick existed.

 

I seriously considered putting my Buick 350 into an 86 Regal limited I had before I lost it in Hurricane Sandy. What I had planned to do was build my 350 much like the level one TSP build and couple it with a 2004r. As for a rear it had all depended on availability. Either you spend the almost 1000 for an 8.5 rear or you spend almost as much on the 7.5 making it strong enough to handle the torque. To build the 7.5 you would definitely need beefy axles, weld the axle tubes, a good girdle and some other modifications I can't quite list off the top of my head since I am no expert on 7.5 rears.

I know alot of people shy away from overdrive transmissions because the initial cost seems fairly high but honestly I think it is thebest bang for the buck purchase you can make. A basic street/strip 2004r can be had for less than $2000 from a place like CK Performance. With a lock up converter and the overdrive you can afford a higher than stock stall and some performance oriented rear gears and maintain complete drivability.

When I went from 2.73s to 3.73s in my Skylark it felt like I picked up 100hp. The car went from 15 second 1/4 mile times to 14.1 just by changing gears. This is all with a stock engine.

Now if you plan on using a G-body all you need is the correct crossmember (something you might have to purchase anyway if you want dual exhaust) and make modifications to driveshaft length depending on what rear you use.

Just reiterating even with a very mild cam like the TA212, gearing and a higher stall will really allow you to make the best of your setup and still cruise the highway at 65 at 2000rpm

 

Here's a quote from another post I made, but kinda buried in the abstract forum posts:

My idea is to have an engine with a similar to stock power band, but with more power. Smooth idle (boom boom boom instead of boomidy boomidy boomidy) and quiet mufflers so it looks and sounds stock. Power band from 1500-4500 (with a wide torque band in the low-mid range) is ideal. Will fit the super turbine 300 2 speed tranny like a glove. Coupled with the fact that it's going into a lighter car, the power/weight ratio will be pretty nice and will satisfy me.

I want the car to last many years, nothing radical or balls out hellion. Something I can drive every day without breaking the bank, can get inside and turn the key over and use, not something that looks nice sitting cooped up in my garage or driveway that I'll just sit there looking at thinking to myself, "gosh sure would be nice to drive it," or spend my weekends tuning, adjusting, prepping, and driving it 1/4 mile at a time. Just a nice car I can have fun with and enjoy until I die.


The point of this thread was mainly to find an ideal sweet spot for such a setup engine wise, try to get away with running regular if possible, and not have to spend a small fortune building it. If this is even possible. I'll take the information recieved and put it to use in the most efficient manner I can.

Everything is pretty much set up in my mind, all that's left is to discern whether the 7.5 is a ticking time bomb or not under this mild, yet potent engine and transmission combo.

Thanks again everyone for all the wonderful information.

 

Not sure what years a G body is,but if they are the 84-87,didn't those come with a 200R4 as the transmission? And if so,why would you want a ST300 instead of the 200R4 that already comes with that car?

You have said that you wanted gas mileage,well that trans will give you that,especially the way you want to build your engine. With a good tune,and 3.42:1 gears,you would get over 20 mpg. The way you want to build your sbb 350 is basically the way I built my 383 sbc for my 65 Impala,it weighs over 4,000 and gets more than 20 MPG on the highway,and it performs very well at the track. I do believe similar results can had with a sbb 350,a roller cam would help A LOT,thats whats in the 383. Dur.@ .050,in 202 ex 212 113 LSA, lift is .550 in .546 ex, it is a Comp XFI grind,but runs very well with a carb.

If the car is going to be a daily driver,then an O/D trans would be a good investment that would pay for itself over time,the more miles you drive,the faster the trans would pay for itself. Lets say you would get a good 18 mpg with the ST300 with a 20 gallon tank of gas you would get 360 miles per tank. And with a 200R4 you get 25 mpg,that would be 500 miles per tank. The difference would be 140 miles per tank,lets say $3.75 per gallon,20 gallons would be $75 to fill up.Then divide 75 by 500 is .15c per mile with an O/D,and W/O is 75 divided by 360 is .2083c per mile. Then .2083 - .15 = .0583c difference. Say you drive your car 10,000 miles a year,you will spend .0583 X 10,000 = $583 a year more for gas without O/D,and remember this was calculated with gas at $3.75 per gallon,which will probably be closer to $4.00 per gallon this summer. Something else to think about before you chose a trans for a daily driver. Results for your MPG may very,depending on your driving style,and how well the car is tuned,and maintained.

In one of your posts you talked about head porting,and you said porting the heads will raise velocity and volume. This is incorrect,when one increases,the other one decreases. On a stock sbb 350 head,the velocity is higher before its ported,and the volume is lower before porting. The reason for porting is to increase volumetric effecientcy,which decreases velocity so more volume of air can fill the cylinder. With good flowing heads and the cam being the limiting factor that dictates how the engine will run. Again,my sbc 383 as an example,it has after market aluminum heads that flow 260 cfm @ .600 lift on the intake,which gives it the potenial for a lot of low RPM torque with the above cam. It will drive down the road at 50 mph around 1,000 rpm with the converter locked without the engine lugging,lower RPM = MPG,and longer engine life.

I hope this helps.

:beer

Derek

 

G-Bodies are '78-'88 GM mid-size RWDs.

Regal, Monty Carlo, El Camino, Gran Prix, ext....

A few had 200-4Rs, others had TH350-Cs, but most had 200R-Metric... An all around crappy trans:Smarty:

I can see your point on the OD trans...

But a ST300 with a switch-pitch would be cool in a G-Body