yellow rose
Overnight Sensation
Hi Yellow Rose,
40yrs ago we sponsered 3 outlaw sprint cars with 350 based engines. Rules then were flat tappet
cams and NO mushroom tappets. So we bored the GM blocks on a Bridgeport mill for .904 lifters and then ramped the cams for them. The chevy mushroom lifters were .925. Tech never found them, they just looked for the mushroom. The GM guy's are just now going to to the .904 lifter for the faster lobe ramp because no one makes mushroom cam and lifters for them.
The Chy mushroom lifters were a full 1" inch in diameter, I have some of both from way back when. Look it up, that is where the old battleship Chy valve springs came from. Heavy lifters at high rpm.
If the weight of the lifter does not matter, what magic force keeps it in contact with the cam lobe other than the valve spring. The only thing I can think of is what is called a Rev Kit. Springs
on top of the lifter so you can run a lighter tension/weight valve spring for ultra high rpm engines. This is before all the newer better rocker arms. The basis for my first post, what is out there that is different/better than 15yrs ago? The only thing that trumps physics is marketing. I did'nt start engine work yesterday I stopped
14years ago. I want to know what is new and you all are using and why? What has been working for everyone. I am now building this engine for myself not others as in the past.
Thank you all
for your posts,
Rick
I’m saying weight on that side of the rocker is pretty much unimportant. Look at what guys have finally started running for pushrods. It used to be that a 3/8 pushrod was all that. Now guys are running 5/8 pushrods, 9/16-5/8 single and double tapered pushrods and as big and heavy as they can get them.
The trade off is that little increase in weight in nothing compared to the power and durability you get out of the big stuff.
BTW, PM me if you want to sell those mushroom lifters. I’ve been wanting a set for donkey years.