I have read on numerous other threads during a google search that .470 is the max. valve lift on stock 113 heads or there will be retainer/seal clearance issues. That the valve guides must be machined to go any higher. I spoke with the machinist at TPIS. He said he had a set of stock 113's with fel-pro seals and that he would run a check for me. He called back and said they were good to .525" lift. Does anyone out there have any knowledge on this? Thanks.

I know that when I installed #219 cam with stock 1.5 rockers I didn't have enough space. That combo is .525" lift. I was using positive style teflon seals. I have #113 heads dissasembled right now, so if you want I could measure from top of the guide to the bottom of the retainer. But you would have to add valve seals that you'll use to that equation

Thanks, I would appreciate that info. How did you rectify that problem, +.050" valve locks, pehaps?

I know some guys have run the LT4 hotcam along with springs in the stock 113s. Here's an old thread from CF, check out post #10.

http://forums.corvetteforum.com/c4-te ... 113-casting-max-lift.html

Thanks, Mat. That's what I like about CF. Ask a question and you get nine opinions about something else before someone actually tries to answer the question.

Quote:

LT4 / ZZ4 spring worked for me ; under $40 set
http://paceperformance.com/index.asp? ... ion=VIEWPROD&ProdID=24732

$20 for the lightweight LT4 retainers
http://paceperformance.com/index.asp? ... ion=VIEWPROD&ProdID=22758


Quote:

A little knowledge is a dangerous thing

Sorry, I didn't have time to measure, I'll get back to you with that info.
I solved my problem by machining (cutting the top) the valve guides.
But when I installed my cam, I also added new double springs and retainers that are (if I remember right) thicker than stock retainers.
I'll measure the spacing on the stock components for you tomorrow.

Thanks. The tech guy at Scoggin-Dickey Chev. also affirmed a .525 lift on the stock 113's. Hopefully these guys are more commited to giving accurate info. than just making sales.

Here is what I measured at stock head. But I can't tell if this head (valves and seats) has been machined before what could give greater readings.




I've also measured on one exhaust valve and reading was .671"
Hope this helps you!

Thank you.