'69 GS- full weight 76 455+.030"- forged pistons- 0 to .010 deck height- trying to get an actual 10:1 compression, reconditioned rods ARP bolts, balanced assembly. '68 400 heads- mild porting, stock rockers. either a Poston GS113A cam, or the TA 286-08H (234, 248 @.050- 112 LC .499 .509 lift). I'm leaning towards the TA cam. 850 holley on B4B intake with 1" spacer. MSD ignition. TA headers, 2-1/2" Xpipe and full 2-1/2" system with dynomax super turbo mufflers. Electric fuel pump with 1/2" lines. 4.11 chevy 12 bolt. TH400 with 3500 stall treemaster MRT converter. Boxed control arms, airbag(s), no hop bars. 26" tall X 9.5" tire. Any ideas what something like this should do in the 1/4? Also, any ideas on how to improve? I am looking for a mid-low 12 second car that will also be street driven on 93 pump gas.
About the electric fuel pump...are you going to run a regulator at all? Too much fuel pressure in a carbureted engine is as bad as not enough. that sounds very similar to setups I've read about here that can run mid to low 12s at about 110 mph, if memory serves. I wouldn't take my recollection as gospel, though.
Thanks for the reply. I will be using a regulator. I'm glad to hear that the combination will probably do what I want it to. The plan is to get it going by next summer, and then eventually go to aluminum stage one heads and go 11's with it. If I only had the $$$$!
'69 462 Hey Steve, Had a similar combo in my '71, went 12'0's as well. My only concern is 4.11 gear with a 26'' tall tire. I feel you may have too much gear. ( maybe someone here could calculate your final gear ratio out) In my case i had 3.73 with a tight converter & 28'' tall tire, i could drive across america if i wish turning under 3000rpm's at 65-70mph. Just my opinion:TU: Randy
I was thinking the same thing, 26" tire and 4.11 gears, I would go with less gear or taller tires. I have 4.11s and 29.5 slicks and it turns about 5900 in the lights with a 3600 10" B/M converter at about 113 mph. Tom
I also would recommend using a taller tire, cheaper and easier than changing gears! 28" should be the minimum with 29.5" or 30" being optimum.:TU: I use Hoosier 29x10 on a 15x8.5 with 4 7/8" backspace. Fits very well :grin: and puts down about the same amount of footprint as 28x10.5, only taller!:Brow: Personally, I don't think you would be able to hook with that much gear and those 26x9.5's. BTW, how come 400 heads instead of 455?? Go with the TA cam:TU: Hope this helps you some.. :beer
Thanks for the suggestions. I'm kinda stuck with the rear end I have. It's a chevy 12 bolt with eaton posi, pro gears (4.11), aftermarket axles, clip eliminators... pretty nice setup. I think the carrier is made for 4.11 and up gears, if I'm not mistaken, or else I would consider backing of to 3.73's. The problem is, being a '69, I'm not sure how tall of a tire I can get under it. I will definitely run the tallest tire I can fit. I also plan to do some work on the wheel wells (is this called a mini-tub?) to help out. Anyone know for sure how much tire I will be able to fit? It is something that concerns me- not so much turning a little rpm on the top end as much as being able to hook it up off the line with a small tire and a lot of gear.
I'm using the 400 heads pretty much because that's what I have. It's either that, or some late model 455 heads. I've heard that the 400-430 heads flow better, and are better to port. Why do you like the TA cam better? just wondering. Thanks for the help :Smarty: :beer
I think I found a solution Looked at summit, and they seem to have a richmond 3.73 gear set for the 4 series carrier! So, if I can't hook it up, I'll have to get one. http://store.summitracing.com/partdetail.asp?part=RMG%2D4900961&view=2047&media=2
Steve, they had to go thinner with the ring gear to make it work on a 4-series carrier!! Careful how much "smack" you put on this one, one of my friends broke a couple of these before he gave up. Kinda reverse of having to use spacer with 4-series on 3-series carrier. Does that make sense to you? I would do your own measuring on your car, as there are several inconsistencies between cars. Rear end width, shift from side to side (which should be fixed if present), suspensions, ect. I've heard that 295 60 15 is the LARGEST that will fit on 68-69. what that exact size is in inches are I don't remember. I think that 28" x 10" slicks on a 8.5" or 10" rim are going to be about the best you can get on '69, depending on backspacing. You may still have to do a little trimming on wheel well lip if you havn't done so already. I would seriously consider keeping 4.10's unless that just won't work for you. Poston vs TA cam?? dunno, just gut instinct o No: :Brow: Hope I'm helping... ou:
I'm glad you told me about the gears! Are the 3.90's the same way? I would assume no, because the 4 series carrier is listed as 3.90 and up. The 4.11's seem to be about right with a 28" tall tire, in my opinion. If I can't hook it up, I will have to look into better suspension. Thanks. Yes, you are helping. It never hurts to get a lot of different opinions.
4.10 & 28" combo, :TU: :TU: Yes! Be glad you don't have 3" exhaust! that makes it real tough sometimes on the rear inside corner Is the rest of your suspension stock in the front?
Right now, everything is stock :grin: (as in, I haven't done much of anything yet). I plan on using the polygraphite rebuild kit on the front. I might end up using moroso drag springs. I'm not sure yet. My dad's '70 with those springs lifts nice and hooks well, but the headers tend to drag quite a bit. Since this car will see a little more street time, I'm not sure which way to go there. As far as the exhaust goes, I am going 2-1/2" because I already have the mufflers. I was thinking of adding exhaust cutouts right after the X-pipe That way, when I go to the track, I can uncap the X. From what I've read on here, everyone seems to say to keep the Xpipe as close to the front as possible, and then use as little restriction as possible behind it. Seem like cutouts would fit that description.
Steve, I've used Moroso drags in the front on three diff 70-72's now on the street. No probs until this car, the 70 GS. It hangs a little lower in the front. I'm not real sure but I think its because the GS is heavier in the hood than Skylarks.o No: I'm planning to go to fiberglass hood and bumper to remedy this. I've already moved battery to trunk. If you were to do these three things, I doubt your headers would ever touch. I even took off the front sway bar. I don't really push it hard enough in the corners to really need one anyways. Besides, during most driving the front is up anyways!:Brow: :grin: I run mine right thru the 3" exhaust! No real need to uncap, and besides it REALLY pisses people off at the track when you don't need to uncork to get an awesome time!!:TU: :TU: :grin: :grin:
I would really like to keep this car all steel. The car is really nice and solid- no rust anywhere, other than some surface rust on the frame (which you would expect of a 30+ year old car). When I eventually build a '69 full race car, it will be all glass- everything but the body shell. This one is going to be a somewhat stock-appearing street-strip car. I would eventually like to hit 11.50's with it. And, yes, 11.5's through full exhaust would be too cool! Maybe with the aluminum heads later down the road.
fwiw If its a hot street or even street strip car as in not a race car consider the 28" tall 275/60/15 Nitto drag radials especially for that gear. Also you might like a 3000/3200 stall better with those gears and for actually driving it on weekends. If primarily a streeter it might help take just enought off the bottom with that cam to help them tires hook. You should not need or probably even want 1/2" fuel line for that combo. 3/8" should be better even for a 3900 pound 11.50ish car. Naturally everyone has an oppinion but lots of 10 second cars with 3/8" line. If you move up to the much better flowing longer lasting Walker Ultra flows or Magnaflows welded as oppossed to super turbos you really won't need cutouts. Keep the super turbos for something else and use the money you would of spent on cutouts on better muffs. Dr gas has a 3" in 2 1/2" out x pipe that might be just right for your application. You could use 3" pipe from header collector to x then 2 1/2 the rest of the way and not have flow restrictions especially if its all mandrel bent pipe. Good luck no doubt it will be a fun car.
Vern, Thanks for the ideas. I thought for sure I would need 1/2" line. I would like to make 550 HP with this car someday, and I don't want to have to upgrade the fuel system later. 3/8 would definitely be easier to work with! 3000 stall... would that make much of a difference over the 3500? I will probably talk to ATI about my combination and see what they recommend, but I wouldn't be opposed to going lower- definitely not if it helps consistency. I will probably be running slicks at the track. As far as the mufflers go, I want something that is fairly quiet for the street. I like the sound of the super turbos. Just enough tone, and not too obnoxious.
All 400, 430, 455 heads are interchangeable, and the 67'-71' 400,430,455 heads are the best of them all. So he is running a good set of heads.
