Hi guys
I am installing GT40 heads on a non-roller 80s block with a hydraulic lifters and flat tappet cam. I am using the stamped steel rocker arms that came on the GT40 heads.
My question is what push rod will work and do I have to change the valve springs?
Thanks
Yes, what they all said.
New build / new camshaft or are you replacing the cylinder heads on an existing motor with established camshaft and build sheet?
If you know the camshaft P/N or specs, you can back into the springs and pick the right ones to match your camshaft... that is not only important but a must, IMO. The camshaft and cylinder heads are the heart of your motor and where you get your performance. Not that pistons, rods and intakes are not important...
If you have a good local shop, they can set the springs up for you by checking your seat and open pressures per the manufactures specifications.
Pushrods... Ø5/16, thru hole and length 'X' depending on your setup. The ones you had in it originally could be a starting point but if you are ordering parts, pick up an adjustable pushrod length checking tool and then you'll know within thousandths of inches what you need for the length. Probably something around 6.75" to 6.95" if I'm guessing and I am just guessing.
DJs74