| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
03-01-2026, 09:44 PM
|
||||
|
||||
1967 GTO HO Ratings
What's the difference between the 335 HP and the 360 HP HO engine on a 67 GTO. Different cam? Different heads? Carb? They both had 10.75 compression.
__________________
Tim Corcoran |
|
#2
03-01-2026, 11:00 PM
|
|||
|
|||
|
Cam, valve springs, exhaust manifolds, air cleaner, carb and distributor calibrations. What have I neglected to mention?
|
|
#3
03-02-2026, 05:37 AM
|
||||
|
||||
|
The compression on both of these motors in actuality was far more like 10.5 to 1.
The 360 hp motor got the standard 670 heads but fitted with stiffer valve springs. They also got the what came to be called the RA exh manifolds, and a open element air cleaner a long with the needed carb recalibration. I would have to check my info but I am pretty sure the 335 hp motor got the 067 cam, the HO motor got the 068 cam for both the auto and man trans cars and the RA 400s which had the 997 heads ( reworked 670s ) got the 744 cam in the manual trans cars. I am not sure what the auto trans RA 400s got for a cam in 67. The HO cars might have had a minimum rear gear requirement which the RA motor certainly did.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
|
#4
03-02-2026, 08:56 AM
|
||||
|
||||
|
Morraine 400 Bearings
TH400 with 3/8 cooling Lines and P_ code. Rear suspension tie bars from Lower to Upper. Coffee hasn't hot yet. |
|
#5
03-02-2026, 04:52 PM
|
||||
|
||||
|
Quote:
HO uses an open aircleaner and RA exhaust manifolds. 335 HP uses the 067 cam, HO uses the 068. Same 670 heads. Same H.D. special valve springs on M/T, same H.D. valve springs A/T. Same ignition distributor, 1111250 (1111252 w/A.I.R.) Same Quadrajet. A/T 7027262, M/T 7027263 (7037263 w/A.I.R.) 3.55:1 (3.23:1 w/AC) std for all except 335 A/T 3.36:1 (2.93:1 w/AC.) |
| The Following 3 Users Say Thank You to Kenth For This Useful Post: | ||
|
#6
03-03-2026, 03:40 AM
|
||||
|
||||
|
Did they use a different thickness head gasket ??
__________________
........... The More You Follow The Herd The Less You Can Be In The Lead .......... |
|
#7
03-03-2026, 07:17 AM
|
||||
|
||||
|
From the info that I have been able to dig up, yes they used different head gaskets.
The 335 hp motor used a .045” that crushed to .038”. The 360 HO and the RA motor used a .033” that crushed to .022”. The compression ratio difference works out to not even 1/4 of a point between the two.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! Last edited by steve25; 03-03-2026 at 07:24 AM. |
|
#8
03-03-2026, 07:43 AM
|
||||
|
||||
|
HO cars also got bigger engine pipes. 2 1/4 vs 2
__________________
WWW.GLASGOPERFORMANCE.COM. Updated... Sort of! |
| The Following User Says Thank You to J GLASGO For This Useful Post: | ||
|
#9
03-03-2026, 08:30 AM
|
||||
|
||||
|
Quote:
i thought 68+ used 2 1/2 with 2" tails. |
|
#10
03-03-2026, 12:12 PM
|
||||
|
||||
|
Having worked for 8 years selling auto parts and looking into what I could do to hop up my everyday GTO without going to headers I can guarantee you that no production Pontiac ever came with anything more then 2 1/4” head pipes.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
|
#11
03-03-2026, 12:46 PM
|
||||
|
||||
|
Quote:
|
|
#12
03-03-2026, 04:27 PM
|
||||
|
||||
|
Yes. Just talking the D port stuff.
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
