# Camshaft problem Need person in the know!



## Buttocks (Mar 13, 2008)

I'm just rebuilding a 1969 Pontiac Gto with Ram air 3 Heads and i'm trying to get the correct cam for the engine. I've been told by a local rebuilder (im in Australia, and he hasnt done one before) 
these are the came specs that he recommended
(I would like the peak power to be around 5300rpm like a ram air 3 GTO)

Precision Cams CM428D
Lobe Spread -112
Lobe centres -Exh 116 Int 108
Cam lift - Exh 296 Int 281
Valve Lift - Exh 444 Int 422
SAE duration EXH 288 Int 276
SAE overlap 59 
.050 Duration Exh 214 Int 204
0.50 Overlap -15
Lash Exh hyd Int Hyd

Any help would be great as where i live there arent any people around that know anything about pontiac 400's
Thanks Heaps Guys


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## Rukee (Feb 8, 2007)

...the ram air cam had 301 and 313 degrees duration for intake and exhaust whereas the standard GTO engine had 273 and 289 degrees duration. 
From here..
Pontiac Performance: 1955-1973½, Archival Ponchos
and...
A Nunzi No. 2042 Ram Air replacement cam features 301/313 advertised duration like the factory 744 cam, but with more lift--0.460/0.470 versus 0.413/0.413. 
From here..
Restoring a 1-of-751 1967 Ram Air GTO - High-Performance Pontiac


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## Chrisco (Mar 19, 2007)

313 degrees of duration has to have some crazy lope to it.


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## 05GTO (Oct 6, 2004)

Is your car a manual or automatic?


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## Buttocks (Mar 13, 2008)

Its a manual
The cam in the first post is actually what the builder installed in the engine and we just put it on the Dyno and it made 285rear wheel HP at 4400Rpm. We are a little pissed that they have put the wrong camshaft in as we wanted it to be more like a ram 3 cam getting max power around 5200-5400
PS: i should of said that the cam was already in, i think i got stooged with the wrong camshaft


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## Old Indian (Jul 4, 2007)

Buttocks,
I've got the RAIII cam in my 400 YS. It's got quite a lope to it in drive, but the great thing about this cam is that it successfully lowered my cylinder pressure to 165-170 without having to change pistons or heads. The power curve continues above the 4400 where yours peaked, but by 5K it's pretty much played out. To get the power curve to continue above 5K, it would take not only the cam, but the RAIII heads and intake as well. Of course, it would also need either an octane booster or a roll back on the timing to prevent detonation. The 1969 Pontiac shop manual from Helm has the specs for all of the Pontiac cams. Here's a great site with some valid information about Poncho 400s. Blueprint Tuning the Pontiac V-8

Bill


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