1970 455 cams,first buick build help

Hello really excited to join this forum. I just picked up my first buick a 65 gran sport post coupe less motor or tranny. The car came with a 3 speed but I'm putting in a Muncie m20 behind a 455 with hopefully a very high geared rear gear (308 maybe). The motor is a stone stock low mile 1970 455 out of a 70' LeSabre 455, the motor is good and I'm not doing a rebuild but I would like to drop in a new cam and intake/carb. The car is going to be an all around performer and I want a nice choppy idle could you recommend a cam that will work well with the stock Heads and 10.25/1 pistons??? Stick shift, high gears and no power accessories.

 

Well sometimes less is more especially with iron heads on pump gas but I've heard others say its closer to 10.5-1. I guess my real concern is piston clearance. I'll check those two cams out. What intake and carb? Would the stock carb be ok with tuning?

 

stock carb will be a 750 cfm if it is the 70 Quadrajet carb. It would be fine, but an 800 cfm Buick quadrajet from 71-74 would serve you better with the extra mods you sound like you are doing.

There are some intake choices, edelbrock performer, and TA performance. I am using TA SP1 for my street driver, and their SPX for my bigger HP car. I like them. I had an edelbrock performer, and wasn't happy with the power. Depends on how you want to drive it. Low rpm cruiser, the eddy would be fine for you.

 

There are other cam choices besides TA. I offer custom cams at a competitive price. Check around, I've done a few for guys on here.

If you're staying with a tall gear then there's little reason to hang the exhaust out a bunch. I'd probably reduce split but keep it on a 112 or so because of the size and compression.

 

3.08 gears, old-school four-speed, and a cam with piss-poor low-rpm manners? Car is going to be a dog to drive around town.

Select a camshaft that makes (usable) power for the application, instead of selecting one to make noise.

 

I'm trying to select one that makes useable power around town that's why I gave my combo/specs and asked for advise. No wear in my post did I say I was wanting a dog. As far as gears i was always told that the low end buick power goes well with high gears and a manual with a low first gear, If I had the budget I'd go with a "new school" overdrive but I can't. Any of you tried any of the comp thumpr cams?

 

Bigger cam, headers, which you will have to do some cutting on the frame in that car and at least 3.73 gears.
After you run it down the strip you will probably be hooked to Drag Racing it!

 

Thanks Larry, I hear what you're saying I guess what I meant is I'm not looking for a sleeper grind so the sound/ vacuum isn't an issue; What is an issue is piston clearance since I don't plan to pull the heads. The car will have full length headers and 3" exhaust. The Muncie is a wide radio.

---------- Post added at 01:32 PM ---------- Previous post was at 01:26 PM ----------

M20 with 2.52 first gear. I might have 3.23 gears in the car not sure yet

 

2.52 and I still need to verify my rear gears. So for this car would you go with one of those cams and the sp1? Or performer?

 

If your M20 has a 2.56 low gear, a 3.08 rear will have a 7.885 starting low ratio and be like starting in 2nd gear in a modern 5 speed. You'll skin some clutch to get going.

Your 2.56 low gear with a 3.42 rear will be OK, but not great with a 8.755 starting ratio.

A performance 5 speed tranny with 3.27 low (no overdrive) and 3.08 rear would be an exciting ride with 10.0 to one starting ratio and good top end to boot.
Stay with a 3.42 rear gear if tranny has overdrive, and scream out of the hole with a 11.18 starting ratio. (3.27 low and endless top speed with overdrive)

TA 288-94 is one hell of a low end cam but idles real good. Great torque at 2500 rpm.

 

I like the 284-88h but I have 3.42 gears with it

 

I don't think that idle is choppy enough. Does anyone got a video of that cam?
I take it you will drive that car on the street most of the time.

 

The choppy idle you're looking for needs a cam with around 10 to 12 degrees of overlap.
The amount of overlap also effects the rpm where the cam "turns on" or where the engine smooths out and starts making torque.

The Comp Thumpr has 20 degress of overlap and engine power doesn't begin until after 2500 rpm.

The TA 284-88 and the 288-94 have 6 to 7 degrees of overlap and may not quite have the choppy idle you are looking for.

I would ask TA to have the 288-94H ground on a 112 lobe center instead of the 114 lobe center.
That will give you 11 degrees of overlap with a choppy idle and a very strong midrange.
You still will have to wait to 2000 rpm before it smooths out.
This would be a lot easier if the 1st gear ratio was in the 3s.

Paul

 

With shorty headers and flow master 40s with H pipe it will sound throaty and deep. I have this cam in a 430.with a 2400 convertor. Ported performer intake.

 

Thanks guys appreciate the advise.

 

Alex is the 430 in that blue skylark? What are you running for headers?