'85 Pushrods
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
'85 Pushrods
Block is a stock dimensioned bow-tie. Have comp-cams roller lifters with tie bar. On top I have comp-cams stainless steel roller rockers.
Switching from a 'small' base cam to a chevy stock '87 vette cam (larger base circle).
Question: Will the current pushrods that I am using work or do I need to get shorter ones due to the larger base circle GM cam? TIA!!!!
Switching from a 'small' base cam to a chevy stock '87 vette cam (larger base circle).
Question: Will the current pushrods that I am using work or do I need to get shorter ones due to the larger base circle GM cam? TIA!!!!
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
The only correct way to tell the size you need is to put an adjustable pushrod in and confirm it. They are inexpensive. The pair of checking springs are also dirt cheap. This is a step so many people avoid doing. It is easy and fast. Trust me, do not take anyones word. Physically check it and be sure.
Melting Slicks
Joined: Dec 2004
Posts: 2,137
Likes: 5
From: Howard PA
We just did this on a 383 we're building. When you consider aftermarket valves, planed heads, decked block and gasket thickness it can add up to a considerable amount of difference.
I think our rods are winding up about an 1/8” shorter than stock. If we had left the stockers in it, sure it would run but the guides would take a beating. We didn’t go so far as to check every rocker, just the farthest valve from center on each head. Yeah it’s a shortcut but any gross alignment problems should be seen easily when the preload is set.
Basically we’re trusting the integrity of the Manley valves used and the machine work of the seats.
I think our rods are winding up about an 1/8” shorter than stock. If we had left the stockers in it, sure it would run but the guides would take a beating. We didn’t go so far as to check every rocker, just the farthest valve from center on each head. Yeah it’s a shortcut but any gross alignment problems should be seen easily when the preload is set.
Basically we’re trusting the integrity of the Manley valves used and the machine work of the seats.
