Pontiac 455 cam recommendation

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John Wallace
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Re: Pontiac 455 cam recommendation

Post by John Wallace »

What heads did he have?

The OP has 6X heads which have small ports (with a small csa at pushrod pinch area) and a long exhaust port that curves like 135º?
Most Pontiac cams have extended exhaust events for this reason.

If they were Edelbrock heads, the ports are a lot bigger (still bad exhaust path but flows a lot better) and could use the same durations.

:?:
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Re: Pontiac 455 cam recommendation

Post by wyrmrider »

to the OP
forum has several Pontiac regulars- John Wallace is one of them
AS and Chad have said exhaust flow makes a big difference in cams
this is not a SBC
It has a heavier valvetrain and slower reving internals
I'm thinking 260 rather than 268 seat timing
see what Jones says
and what the guys that run Pontiacs say, one so far
is this around town or a freeway flyer?
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Re: Pontiac 455 cam recommendation

Post by 427dart »

How about the Pontiac Ram Air manual trans cam 301/313 I think it was. Or if you want milder the old HO/Ram Air automatic grind 288/302.
Was a Pontiac man years ago and the factory had those Ram Air engines dialed in well!
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Re: Pontiac 455 cam recommendation

Post by tjs44 »

just not enough cam for a 455 IMO.A RA IV does very well in street 455s.Tom
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Re: Pontiac 455 cam recommendation

Post by GARY C »

427dart wrote:How about the Pontiac Ram Air manual trans cam 301/313 I think it was. Or if you want milder the old HO/Ram Air automatic grind 288/302.
Was a Pontiac man years ago and the factory had those Ram Air engines dialed in well!
In my 20's I had a 4spd 77 T/A with a 400 6x head Ram Air III cam an eldelbrock performer intake with a 650 holly and 2.73 gears and a 79 auto T/A with a stock 403 olds and a 2.41 gear that my girlfriend drove... guess which one was faster?
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Re: Pontiac 455 cam recommendation

Post by Walter R. Malik »

John Wallace wrote:What heads did he have?

:?:
Whatever heads came on a 1975 400 cubic inch engine and modified to a 45 degree valve job with mild bowl porting.
The OP gave flow numbers which were real close.
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Re: Pontiac 455 cam recommendation

Post by tjs44 »

The OP said 461 CI!What does a pontiac 400 have to do with the thread?It has a 1/2in longer arm?Tom
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Re: Pontiac 455 cam recommendation

Post by CGT »

cstraub wrote:That engine had an I/E ratio in the low 50's.
cstraub wrote:This engine and any other NA engine with that kind of I/E ratio needs a reverse split camshaft.
I/E Ratio's!
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Re: Pontiac 455 cam recommendation

Post by Walter R. Malik »

tjs44 wrote:The OP said 461 CI!What does a pontiac 400 have to do with the thread?It has a 1/2in longer arm?Tom
Longer arm than a 480 cubic inch engine which has 400 head castings from 1975 ...? (4.211" bore x 4.310" stroke)

Your comprehension needs some improvement.
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Re: Pontiac 455 cam recommendation

Post by GARY C »

Walter R. Malik wrote:
tjs44 wrote:The OP said 461 CI!What does a pontiac 400 have to do with the thread?It has a 1/2in longer arm?Tom
Longer arm than a 480 cubic inch engine which has 400 head castings from 1975 ...? (4.211" bore x 4.310" stroke)

Your comprehension needs some improvement.
I think that was directed at me.
From the OP's post...Old school Pontiac says to go wide lsa and dual pattern cam. Vizard books tell me tight lsa and single pattern cam
I included my 400 because I used to think a Pontiac needed a Pontiac cam until I learned that the cam doesn't know the make of the engine.
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Re: Pontiac 455 cam recommendation

Post by pmd400 »

How would 276/268 adv. 233/227 at .050, .504/.489 lift with 1.5 rockers lunati voodoo sound.
I'm thinking 106lsa ground on a 102icl
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Re: Pontiac 455 cam recommendation

Post by wyrmrider »

WTF
Pontiacs, Olds, Cad ARE different than SBC
Start with the springs and the valve weights,long flexy pushrods
hit the throttle they just do not rev up as quick
cam can't be as radical and live
now work with the head flows and what Chad said I used to use single pattern cams on these with 1.65 on the intakes only
All those stock cams are really obsolete
Did not Harvey Crane put them through his "cam smoothing" process?
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Re: Pontiac 455 cam recommendation

Post by tjs44 »

Guys,im not the sharpest tool in the shed BUT I drive a lot of pontiacs on the street from a 366 NASCAR tunnel port engine to 455s with all diff heads.This guy is looking for a street engine to work with power brakes and from what I get drive well.In the last almost 20 years I have street driven cams from 108 to 113 and duration at 50 up to 252-260.ALL have been stick shift cars some with 4 speeds but most with TKO 5 speeds.With a iron headed 455 and 9.5 CR on out CA 91 piss gas a 245-252@50 on a 110 got me one really solid power brake stop without a vac assist.When going wider to a 112 it was better.With a 250-250 on a 108 with a 3.90 rear gear it did not like being under 1800 rpms around town in 5th gear and had to be pulled back a gear.236-242 ish on a 112 seems to be a sweet spot for my street driving with a OD trans for me.Have not given a tinkers damn about peak HP as all the engines are street drivers with street manners.I built one 455 with a Summit 2801(RA III cam) straight up.It pumped 200 and had to ad race gas to street drive it.Im only giving my experience about street driving these engine for the last 20 years.Post on.Tom
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Re: Pontiac 455 cam recommendation

Post by Walter R. Malik »

pmd400 wrote:How would 276/268 adv. 233/227 at .050, .504/.489 lift with 1.5 rockers lunati voodoo sound.
I'm thinking 106lsa ground on a 102icl
In my opinion, to big for an often driven around town vehicle; (unless you put a bunch more gear in the back).
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Re: Pontiac 455 cam recommendation

Post by 427dart »

Compared to all the "new" way to design a cam for a particular engine...were all the factory engineers just guessing when developing a cam for engines back in the late 60's? Pontiac had Malcom McKellar design their factory race and street cams...one of the best back then.
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