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Civilian
Tribal Scout

19 Posts

Posted - 10 May 2015 :  9:55:10 PM  Show Profile  Reply with Quote
Hey there, this is my first time I this site and I need a little help. I am currently building a 1962 Grand Prix with a 1972 455. Engine is 0.030 over, supercomp forged Pistons, stock crank, 6x heads with taller springs (no other mods), XE274H cam (can provide specs), planning on 700r4 from Hughes, 2000stall and 4:11 gears.

The dilemma: I have an old edelbrock performer and some sort of single plane intake. I would like a performer rpm, but trying to save money where I can.

The question: can I open up my performer intake to get some better performance, or should I just suck it up, pay the money for the performer rpm, and don't tell the wife?

Next question: what carb does everyone like for Pontiacs? I am a younger guy who has only built a small block ford for my '66 mustang. The only experience I have is with the edelbrock 600cfm for that car...which I only had to bolt on. I have been seeing that guys seem to like demon carbs on Pontiacs, but wanted some opinions.

Thanks in advance!
Jason

cortcomp
Coyote

USA
5335 Posts

Posted - 10 May 2015 :  10:01:15 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Performer RPM if you can (used are like $75) and carb, pontiacs love a qjet for the street.
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Civilian
Tribal Scout

19 Posts

Posted - 10 May 2015 :  10:05:55 PM  Show Profile  Reply with Quote
Thank you. Sorry for my ignorance, but does the quadrajet come in different sizes? What size do you recommend?
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cortcomp
Coyote

USA
5335 Posts

Posted - 10 May 2015 :  10:08:54 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Well, in a 455 with the XE274, you'll not be revving super high, so a 750 or 850 would be good. Most parts warehouse rebuilds are a mixed bag of luck. Cliff will hate your cam, but read his book on qjets, how to rebuild quadrajets and pick a decent recipe.
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Civilian
Tribal Scout

19 Posts

Posted - 10 May 2015 :  10:12:37 PM  Show Profile  Reply with Quote
I will do that, thank you. I had the hardest time deciding on the cam, and just placed the order the other day. Just what I need...another reason to doubt my selection!
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cortcomp
Coyote

USA
5335 Posts

Posted - 10 May 2015 :  10:39:23 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
With those heads there's not a lot of other options. I had the XE262 and the XE284. I was happy with the under 5500rpm power, but hated the valve noise on the XE284. I'd consider a similar voodoo lobe if doing all over again.
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 11 May 2015 :  01:13:08 AM  Show Profile  Reply with Quote
Factory iron will out flow the performer. Hard to beat an iron intake with iron heads.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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2barrelpower
Sitting Bull

USA
135 Posts

Posted - 11 May 2015 :  01:18:32 AM  Show Profile  Reply with Quote
According to Jim Hand's book, the Edelbrock Performer 2156 and the factory q-jet intake perform the same.

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 11 May 2015 :  07:42:03 AM  Show Profile  Reply with Quote
On that particular combo that was true. But the performer is a "replacement" (generic) for 326-455 engines. The runners are second rate to the factory intake. It's not conjecture, it's obvious to the naked eye. They work well on 350's and stock-very mild 400's. On your combo, the performer would most likely be a choke collar. Of course, an edelbrock carb would mask it as it would be an even bigger problem.

Why the 4.11 gears? Way out of line with a high torque/low rpm pontiac 455 and the problem is greatly compounded by the super short 3.06 first gear in the 700-R4.


Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5335 Posts

Posted - 11 May 2015 :  08:33:48 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I missed the gears, 3.42-3.73 is where you will likely want to be with OD. I had a stick with almost the same ratios as the 700-R4 with 3.91s (moved to them from 3.42) and i felt it was a little too much, i wished i had went 3.73s after doing the 3.91s.

With 4.11s, you're building something that winds up but a 455 and the XE274 in a 455 are not really 6k rpm setups.
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Civilian
Tribal Scout

19 Posts

Posted - 11 May 2015 :  1:31:25 PM  Show Profile  Reply with Quote
Thanks for all the help guys. To be honest, I don't know what I'm doing. My thought process was that a high gear will help me launch from stoplight to stoplight and the overdrive transmission would let me drive it on the highway without running at a super high rpm. I would definitely listen to any suggestions you guys have. ANY suggestions.
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cortcomp
Coyote

USA
5335 Posts

Posted - 11 May 2015 :  2:17:10 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
A 455 will be torquey so you'll always be good stoplight to stoplight. 3.08-3.23 or numerically lower for non-OD, 3.42 to 3.73 for OD. May be slightly different for OD without locking converter? Mine was stick, and i ran 2.56s, 3.42s and 3.91s, so i have a decent idea of how it will feel around town and on the highway.
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Steve C.
Crazy Horse

1675 Posts

Posted - 11 May 2015 :  6:07:40 PM  Show Profile  Reply with Quote
Not apples-to-apples, but with my TH200-4R trans w/3.73 gears I use a Continental non-lock up torque converter and it has about a 200 rpm slip at a steady state cruise speed on the open highway. About 2300 rpm at about 70 mph.

Edited by - Steve C. on 11 May 2015 6:08:14 PM
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Civilian
Tribal Scout

19 Posts

Posted - 11 May 2015 :  8:33:20 PM  Show Profile  Reply with Quote
That's actually helpful too Steve; thanks!
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 12 May 2015 :  12:40:27 PM  Show Profile  Reply with Quote
With the 4.11's you will hate driving any further than a few miles. On the highway, even with overdrive, it is overkill. No need for it with a 455. My 461 with 3.55's and a turbo 400 tranny will rip through all 3 gears - no problem. I do wish I had an OD tranny though for all the long highway runs I take.
Last engine was a 400 with the same rear and tranny - it too would spin through all 3 gears.
With 3.23's through 3.73's, you will be fighting for traction all the way under full throttle. The 4.11's will just eat tires even worse.

I guess my point is, do not do 4.11's .... You will hate them unless you are building a pure 1/4 mile car. Even then - overkill with a big Poncho. They are torque monsters. 4.11's are great for small blocks.
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2barrelpower
Sitting Bull

USA
135 Posts

Posted - 14 May 2015 :  02:48:50 AM  Show Profile  Reply with Quote
The RPMs with 4.10s and the stock tire height with overdrive is fine. See for yourself here: http://www.wallaceracing.com/gear-speed.php

I do agree that 4.10s are for drag cars and small blocks.

I don't know what the ideal Pontiac gear is, but I know it's less than 4.10.

69FB, 350P, 9 to 1, Comp 260H, Stock Valve Train, Performer Intake, 1406 Carb, Hooker Headers, Points Style, Crane XRI, Crane PS20, TH350, stock stall, 3.08 gear, and 235/60/15 Firestones.
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