I think it really is understated just how big of an improvement the 2004r is over the 2 speed and 3 speed transmissions that Buick engines are normally coupled too. For racing they are great, and if you have gobs of torque like you would with a 455 then you don't need short gears to get you going. But for a mild, stock sounding daily driver like you plan for your 350 an overdrive can only help you. It will be plenty strong enough and it is the same length as a th350 so whatever driveshaft you intended to use with a th350/st300 you can use with the 2004r. This is definitely a cheap way to gain some oomph and also some efficiency. That is the last bit of persuasion I have left to try and convert you to overdrive:laugh: Turning to your other issues, I think the 7.5 will be fine, IF you take the necessary steps to prepare it for 400lb ft of torque. An expert can point you in the right direction, but even poking around a G-body website I am sure you can find a thread that lists the parts and steps you have to take to have a reliable rear end. The Buick 3.8 is pretty much the 350 with 2 cylinders lopped off when it all boils down. I have been toying with the idea for years of either putting a fuel injected 350 in a regal or even an SFI single turbo setup that would look almost factory to the untrained eye. The 3.8 is probably one of the greatest American designed v6s ever produced. It shares almost identical block architecture to the 5.7, so we know that what ever power a 231 can stand, the 350 can do it as well. Now we just need to wait on the aftermarket to catch up to the desires of enthusiasts. Some of us can dabble here and there in some custom stuff but we will really see the potential come out when we get some good aftermarket parts in the hands of experienced builders. I'm not trying to side track your thread, only trying to get you to think about some of the other angles you can approach this project. It may take more time and/or money, but in the end you could more thoroughly achieve your goal. We all know how well a fuel injected 455 can perform, so a 350 can most likely surpass those MPG figures and still reach each of your targets. Whether you used a setup like this from TA Performance, used an EZ EFI setup or Megasquirt kit, or even made something yourself using the factory 231 fuel injection, I think you could really have a car that performs better and is just as efficient as most cars being produced today.
Derek (and everyone else too), I appreciate all the input you're giving me, and it's helping. I don't recall posting anything about head porting increasing velocity and volume (as in simultaneously), but I do recall saying there are two aspects to flow: velocity and volume, and that there are sub-aspects of each to help each be more efficient. Velocity is the speed of the charge, and volume is the quantity of the charge. Shaping the runners properly improves the quality of both, in terms of how well the air/fuel gets mixed and stays mixed, and how it's channeled into the combustion chamber. Keeping velocity up through mild port work by port matching and keeping runners shaped similar to stock, shaping the bowls around the guides improve flow quality by reducing turbulence. Volume is in effect increased while maintaining good velocity for good charge characteristics. I'm certainly not a pro here, and my terminology may have gotten mixed up? Either way, port matches and bowl blends and exhaust polish is what I plan on doing, regardless of the semantics. Probably use the TA RV-12 cam and 9.5 comp. DCR should be at or less than 8:1 and the engine will be sufficient. I also said the st300 wasn't a solid plan, but that was an ideal for me because I remember how well the 350/300 setup was in my old '68s and how much I enjoyed them. If I have to change the axle, I might change some other things around altogether. The G body went from '78 to '87, maybe to '88 in non Buick form, not positive on that. The G body is an ideal also. Depends on what I get my hands on. I don't actually have the car yet, I'm just making plans for when I do, so I can make a more educated decision on my investment. An X body would be cool too, or even an A body. Hell, I'd even be happy with an old B body LeSabre or Centurion or whatever. This engine will pretty much be suitable for anything with a highway gear. (or a mid-gear with OD) I know I came here wanting to look up a thing or two, and got sucked in. I didn't realize just how much I DIDN'T know.
Heres a helpful article that explains when volume goes up,velocity can only stay the same or go down; http://tictac-4g15.blogspot.com/2012/01/head-flow-vs-velocity.html
Good article describing the terms, I guess my trying to explain it didn't pan out so well, though I can see it in my mind. Like with trying to push more air through the same size tube, velocity will increase, but if you open that tube's diameter up, it will go down, but flow will be increased. In order to increase velocity again, more air has to pass through the tube. (as with more CID or higher rpm or both) Akin to boring and stroking an engine without doing anything to the heads, velocity will increase. The opposite is true if you increase runner size without changing the CID, where you would have to raise the RPM in order to regain any of the lost velocity, which is why the bigger ports/valves you go, the better the heads are for higher rpm usage. Conversely, retaining similar to stock diameters, but improving the characteristics of the movement of air (I won't say flow anymore) by removing any ridges (i.e., port matches and bowl blends and exhaust polish), it still improves volume a little (because turbulence has been reduced), but retains more of the needed lower rpm velocity so the charge can get to the combustion chamber asap without any fuel dropping out of the charge. Did I say that right? Although intake to head port match needs to be done, and head debur and cleanup on intake runners are beneficial, retaining some material texture is necessary for adding just a little turbulence to the air and fuel (texture depth varies with flow/velocity needs) as it moves through the runner, to help keep the air and fuel mixed. In fact, there are techniques involved that actually swirl the charge before it gets to the bowl, then the bowl is 'bowl rolled' and finally the swirl polished valves give the charge a 'twist' as it enters the combustion chamber. On the exhaust side, it's just the opposite, you want it as smooth as you can possibly get it, so there is as little turbulence as possible in order for the exhaust to be expelled, and in fact helps with scavenging. Am I getting warmer? The way the heads are ported are more important than simply opening them up. You can actually harm the engine's performance if done incorrectly. At least this is what I was taught as a lad from an old school racing engine builder in Atlanta. I won't need all this fancy stuff on my engine, just a simple portmatch, bowl roll, and exhaust polish should do the trick with the RV cam.
I've nothing against a nice 8.5 with a 3.42 slimited limp and a 2004r. I've toyed with every combo imaginable, including leaving the v6 in it and just beefing that up, but the N/A v6 would never compare to what I really wanted. Thought about different kinds of engine/tranny combos. 350 would be the easiest and cheapest, aside from the v6. I think people underestimate the advantages the st300 would give too, especially to those who've never had or used one. Aside from being easier on the drive train, they only take 18 hp from the flywheel, as opposed to the 44 hp a th400 takes and 36 from a th350. Not sure about the 2004r though. 26 hp difference between a th400 and an st300. that's pretty substantial, and is 'free' power simply by choosing that trans. Switch pitch would be sweet.
I am using a SP-TH400 in my turbo car since I prefer the better gearing of that trans over the ST-300... I see your point about less HP drag off the trans but the gearing disadvantage is huge comparing the 2 speed vs the 3 speed. Each to their own, but I am not concerned with giving up a few HP to a stinger more durable trans.
I cant honestly see the advantage of a 2 speed trans. over a 3 or 4 or 5 or 6 speed. The more gear ratio's available, the more time the engine can stay in its most efficient rpm band.
With all due respect: To each their own indeed, but a mild 350 is in no danger of harming the st300 (I've had a 10:1 455 in front of an st300 and it held up just fine), and if it were in fact 'only' a few hp, that would be true. As far as the gearing disadvantage, testing with the nailhead lovers show only a little lost on the et, but in fact improved mph. So holeshot advantage is trimmed back slightly, but top end is actually better. Besides, this isn't a drag car, and I do not intend on taking it to the track, so my advantages of using a 400 is zero, unless it was SP, then that would be fun. But in MY scenario, I'm not running a turbocharged 350, and totally do not need what you need. 26 hp isn't as much of a loss to you as it is to someone who has 300 hp. I'm not here to convince anyone of anything, just to express my POV and reasoning on my decision.:bglasses: I have actually owned two st300's before and loved them. I've swapped out an st300 for a th375 behind the same engine, and I can say from personal experience that the difference is indeed huge...but not like you describe. The holeshot is indeed slower, but not by THAT much, and by the time I got half-way wound out in 2nd gear, I could tell a big difference in power loss. When I hit 3rd gear, it was like pulling uphill with a 50 mph headwind compared to the st300. The gearing disadvantage is huge...on paper. To actually use it, though...what can I say? That's my experience. ---------- Post added at 01:08 PM ---------- Previous post was at 01:02 PM ---------- Yes, on paper this is true. If you have a torque-oriented engine with power concentrated in low-mid range, the combination is actually quite impressive. When the engine has a broad torque band, like the Buick engine does, it is in fact staying in its efficient rpm band. As for racing, well I can't vouch for that experience. I loved those st300's I had. Sorry! lol Whatever tickles your pickle bro
Having had an ST300 in a 67 Special 300ci and the Olds equivalent in a 66 F85 330 2bll I agree with Gary, they are an under appreciated tranny. With the switch pitch in hi stall I'm sure that the overall ratio is not a lot different than a TH350 at launch plus they held "low" to ~72 mph. I know that whatever I lost off the line was usually made up as soon as the opponent shifted to second. Those were completely stock cars tho. That being said I will be using a 2004r in my 72.
Availability will probably be another issue, admittedly, though it's not a must for me. It would be sweet though! The st300's I had were non-SP in '68's, and they did very well. I can only imagine how much better they'd have done with a SP converter. If GM was doing away with the st300 in '69 and introducing the th350, I wonder why they decided to ditch the SP versions for '68's? I feel cheated.
Look up the maximum torque rating for those light trans with their light parts and lower rotational masses. In general, the lighter the parts, the lower maximum torque they are rated to withstand. This includes 200R trans that were not built for a GN or later beefed up with special parts that are expensive relative to stock. I recall a TH400 is only rated stock to about 450 ft lbs. The parts in it, like the mainshaft, make a 200R, a TH350, ect, look like tinker toys. I suspect you would say the same about a ST300. Those trans are rated really low for maximum torques but I do not recall the exact numbers. So there is a very good reason the rotational mass losses are less in these light duty trans.
One of the '68's I had was a LeSabre that came with the st300 and a 350v4. I took the 350 out and crammed a 455 in it from a '70 electra. The performance of that car was scary, and the st300 held up no problem. Never had issue 1 from it in all the time I drove the car, and I wasn't easy on the car at all. It had a 2.93 axle and a crazy high shift point in drive, coming out of low at 80 mph into high. The 350 I think shifted at 78ish. Not sure what the '68 LeSabre weighed, probably 4200-4400? That was some serious strain on the st300 I would think. When I had the 350 in it, I would frequently neutral drop it into drive. Never did that with the 455, since it had no problems at all spinning those tires! I even disconnected the detent solonoid so it wouldn't downshift from high, and would hold the 455 wide open at low speeds to test the transmission. No problems. Ever. Low and high holds up to at least that. As far as its breaking point? I have no idea. I just know it'll handle some torque. In a lighter car such as a G body Regal and with a mild 350, I don't foresee any durability issues at all. The only thing that concerns me is using it with a 7.5 axle. ---------- Post added at 05:53 PM ---------- Previous post was at 05:47 PM ---------- Those numbers don't seem right to me. ST400 and TH400 came standard behind big blocks that made more torque than that from the assembly line, even with the fudged dyno testing. All I can say is what I experienced. I have no reason to lie or mislead.
I have known a few people that smoked most of their lives but they did not die due to a matastasized lung cancer. You were lucky, and no, they are not built even close to the same maxmum torques ratings. ---------- Post added at 06:58 PM ---------- Previous post was at 06:55 PM ---------- I have known a few people that smoked most of their lives but they did not die due to a matastasized lung cancer. You were lucky, and no, they are not built even close to the same maxmum torque ratings.
Living in Clarksville, TN right now, but was born in Fostoria, OH. I've lived in GA and CO too. Had my Buicks in GA back in the late 80's and early 90's. Abused the hell out of them, didn't appreciate what I had as a 22 year old I guess. Figured, ah, I'll get another one one day... Life goes on and happens, and 'one day' hasn't come yet, so I have to make plans. Sure do miss being 22 and having a Buick. lol
