Hey guys, I am finishing my 70 Skylark convertible GS clone and I have decided to put a 350 4-Speed set up that came out of a low mileage 70 GS 350 years ago. I talked to TA performance and after explaining that the car will be a summer driver and may see the track once or twice a year, this is the build I decided on. .030 over pistons, aluminum stage 1 intake, 290 94H cam (+ lifters & stock pushrods) Stage 1 valve springs, 1.920 intake valves, 1.550 exhaust valves, 750 CFM quadrajet, stock distributor with a Crane cams points eliminator, 1 3/4" headers, and 2 1/2" Flowmaster exhaust (p/n 817409). I am fortunate enough to live down the road from The Quadshop and I trust Jim with a quadrajet over an out of the box Holley or Edelbrock. Obviously a M-21 4-speed behind it, and the stock 3:23 posi from the GS. Any suggestions that would make this a more powerful build while still maintaining streetability? I wouldn't mind stepping up the gearing to a 3:42 or 3:64 if I can find the parts. Just kind of curious as to what kind of horsepower numbers or 1/4 mile times I should be expecting. Anyone running a similar set up? P.S. I know the color I chose isn't a factory Buick color.... It is a special order 70 Oldsmobile color "Aegean Aqua". I couldn't resist this color when it came time to choose.. Currently has a white top and pearl interior as well. Still kept my GM all GM haha Thanks, Mike
A Side note--> if you need OEM restored 350 BUICK clutch fork and bell crank, I have those and don't need them. $300 shipped. Nice looking ride there! Cheers! MarkO
With that cam I would think a single plane intake and 3.70 gears would really rock. Would give up Alittle mpg though.
Yea, I talked to TA about the intake options. Said if I got the compression up high enough, then the single plane would be the answer. But I would run the risk of it being a little lazy off idle if it's not done right, so I played it safe with the Stage 1 replacement. I definitely don't fear the gear as long as it can still be a highway car. If I was concerned about gas mileage, I would be doing an LS swap!
who is doing your engine? measure piston depth to get actual compression ratio. block deck height will be higher then blueprint. aftermarket pistons don't seem to be at proper specs either. also 70 head gaskets are thiner shim gaskets at .020. replacement felpros are .045. with a drop in compression . if your pistons gave .058(stock spec)piston depth with .045 gasket and 10 cc piston dish you would have about 9.3 compression with 70 hi compression replacement pistons if they measure properly. if you milled .025 off block, and had a piston depth of .033 you would have about 9.8 compression. that should be a decent ratio for that cam. with a manuel trans you shouldn't have to be too worried about a soft bottom end
It sounds like a great setup! Have you considered the alum 350 heads? They will be released very soon.
If you go with steeper gears*, I'm sure there is a ready market for those 3.23s you've got. *I probably got that backwards, I always do.
http://www.v8buick.com/showthread.p...&highlight=70'+post+skylark+back+at+the+track Check out this thread.. Cam is ta 310. Just slightly bigger that the 290 should give you an idea of where you may be at. I'm have the 310 cam in my convertible but am considering droping a Crower level 3 in it when it gets back from interior and top shop. But would also need to change back to dual plane intake,change stall from 2800 to 2000 and bump from 3.73 gears Down to 3.23 or maybe 3.42 max
Thanks for the advice, I am having a shop in Sterling, IL do the work. I will be sure to forward this information to him.
If I could be in the low 13's, I would be one happy camper. I was thinking it would be around a 14 second car with this set up, but I would love to be wrong!
I did consider this......but they said $2500-$2800 for them... I had to pass considering all the other parts cost me under $2000. If I was going to invest that much money, I would have followed my original plan to just buy an LS2/T-56 swap and have a 400 HP motor knocking down 20+ mpg.....But I decided to keep it all Buick.
I don't think 13s will be a problem if your good with shifting and you get the compression up north of 9.6 and the big valves. But need Alittle more gear. I think traction will be your problem. Don't forget to get a recurve kit for distributer. With 32 degrees of advance all in by 2500 should be good to start tuning
For comparison, I'm running a '69 350, .030 over with TRW forged pistons, TA290-94 cam, stock intake, stock points ignition, re-jetted quadrajet carb, TA headers, 2 1/2" muffler shop bent exhaust with an X-pipe, T350 trans with a shift kit, Daaco converter that's just above stock stall, and a 3.23 posi rear. With street tires and rolling into the throttle to keep from spinning it's run a best of 13.65 @ 99mph with a 2.0 60'. More converter and better tires are needed, but it will really lay down a nice patch of rubber from stop-lights as is! I've driven it on 800+ mile road trips and if I stay about 65mph it'll run along at 2900rpm and get about 16-17mpg with stock P215-70-14 radial tires. I did have the TA intake on it for a couple years, but it didn't run any faster so I went back to the stock intake so I could run the Pure Stock Modified class at my local track. The headers bumped me to modified, but they really helped the engine breath and improved my times by about a half-second.
Who are you using in Sterling? I'm over near the Quad Cities, but Sterling is close enough to consider too.
I'm curious why you didn't keep the intake on or I guess more accurately why that would bump you out of the Pure Stock Modified class while headers don't do that?
That was just the way they wrote the rules, headers were OK but no aftermarket intakes allowed. Car ran just as good with the stock intake as with the TA so I sold the intake to buy other stuff.
