Pushrod Length?

I'm not sure what pushrod size to use. It seems like I should use the 302 rods, but wasn't sure which length. I was thinking 6.900 or 6.950...

Here's my setup:

289 Block
Solid Flat Tappet Comp Cam
1970 351W heads w/ chevy valves
Comp Cams Roller Tip Rocker Arms

Anyone have an idea?

You will need rocker studs with no stop. the Chevy valves will throw off the geometry so to be safe you will have to check where the rocker rides the valve.

You know, it's really funny. This mod has been done sooooooooooo many times by soooooooooo many people over the years, you would think there would be a pushrod for this application. Or that someone would have an answer. Then there's always some wise-guy chiming in about using a pushrod length checker and ordering custom pushrods. This is an old school trick. I can't belive nobody can ever answer this question. Maybe the old timers never worried about the geometry and just ran the stock pushrods. One of you old farts has to be able to answer this question. It's driving me nuts!!!!

I can't tell you what length pushrod you should use , but would like to make a few points. I guess I'm just a wise-guy. Just because you use a pushrod length checker doesn't mean you have to order custom length pushrods. If there is a junkyard solution to your problem the checker will tell you that as well. Perhaps the old timers weren't running perfect length pushrods, but the checker will tell you what the closest to perfect is. You do what you want, but, as you already said, maybe the oldtimers didn't care about valvetrain geometry, so when one of them pipes up with the wrong length pushrod, are you just going to buy it? I wouldn't feel very comfortable running a non-standard set-up without verifying pushrod length, but maybe you would prefer building your motor and using your ears to verify length.I'd rather know I had it right the first time. If I was going to take anybodys word for it, I would go to Summit Racing. com and ask a Tech for their recommendation.

Originally Posted by Cleveland_Rocks

You know, it's really funny. This mod has been done sooooooooooo many times by soooooooooo many people over the years, you would think there would be a pushrod for this application. Or that someone would have an answer. Then there's always some wise-guy chiming in about using a pushrod length checker and ordering custom pushrods. This is an old school trick. I can't belive nobody can ever answer this question. Maybe the old timers never worried about the geometry and just ran the stock pushrods. One of you old farts has to be able to answer this question. It's driving me nuts!!!!

Anyone who tells you what pushrod length will work on YOUR particular combo without seeing it is just making a guess. Cleveland Rocks, so you think any 289-302 block with any 351w heads and chevy valves would use the exact same pushrod length? So different amounts milled from the heads and/or deck, different head gasket compressed heights, different cam base circles, different lifter types, etc., etc., etc. wouldn't make a difference? Anyone who has a clue would use a checker and order the closest length pushrod available through comp, crane, etc. You don't need a custom pushrod from someone like Manton for what most of us are trying to do. The Comp Hi Tech checkers work great and are money well spent at about twenty one bucks through Summit. It's way too easy and cheap not to do IMHO. Then again whats a little side loading on the valve, lost lift at the valve, possible retainer clearance issues, etc going to hurt? LOL!

What I was saying is that this mod has been done a billion times over that there should be some common knowlege out there about what works. With the assortment of different valve sizes available these says this trick is obsolete. Just buy the right valves for your head. But this used to be the common thing to do, so there should be lots of good info out there.

Thier is no Standard Length for any performance application, You need to measure due to different heads, Rockers, Base Circle on Cams, deck heights, Ect. If your building a engine and do not have the ability / Skills or can't learn too measure for a pushrod, you have no business assembling and engine.

The proper Way to get the correct length pushrods is to MEASURE and get the CORRECT length.

Its not a wise guy Response its the Right Response.........

Originally Posted by 289nate

So different amounts milled from the heads and/or deck, different head gasket compressed heights, different cam base circles, different lifter types, etc., etc., etc. wouldn't make a difference?

Cleveland Rocks which part of this don't you understand?..Way too many variables in a build to say a certain pushrod length will work just because it is a supposedly "common" buildup.

Back in the day before affordable roller tipped and full roller rockers not much attention was paid to push rod lengths. Stock length worked most of the time. Nowadays it would be wise to check lengths with a checker as the other guys have said. Here's my shirt:

Originally Posted by dfree383

Thier is no Standard Length for any performance application, You need to measure due to different heads, Rockers, Base Circle on Cams, deck heights, Ect. If your building a engine and do not have the ability / Skills or can't learn too measure for a pushrod, you have no business assembling and engine.

Originally Posted by dfree383

The proper Way to get the correct length pushrods is to MEASURE and get the CORRECT length.

Its not a wise guy Response its the Right Response.........

I agree it's the right response, but it's not a very polite one. Take one sentence out and it would be well received.