351w buildup advice

[His Royal Ghostliness]

The problem with used performance heads is the same as the one with used factory heads - you don't know what they've been thru, and what work they'll need. They may have very well been put thru hell and not show much of any indication of it, especially if you're buying them online and having them shipped.

Most aftermarket heads do come with 3/8" studs already, guide plates included usually. It's a much nicer setup than the pedestal mount, stronger too. PEdestal is great for factory setup tho... Tell you what is a stupid setup, GM's pressed-in studs.

[gadget73]

Last used set of heads I bought were GT40P. Got a fairly good deal on them, low miles, removed for an upgrade, blah blah blah. They looked good. I dropped them off at the machine shop for a checkup and to make sure the valve springs were going to be appropriate for whatever I had in mind at the time. 5 bent intake valves, 3 bent exhaust valves. The intake valves couldn't be matched so it ended up being 8 new intake, 3 new exhaust, plus whoever had cleaned them after removing the heads had ground the gasket surface uneven enough that they had to be resurfaced. Once all that was done, it was no longer a very good deal.

Aftermarket heads could be the same situation.


I've dealt with press-in studs that were un-pressing. They work ok for stock springs but with a lot of lift and a lot of spring the studs just walk out. Only thing you can do is have the heads machined for screw-in at that point, and clean up whatever carnage happened to make you aware you had a problem. Usually its a couple bent pushrods at least. I saw that on a marine big block that some dude at the marina had. It started hammering and I found the bent stuff. It also just looked a little bit wrong. Straightedge across the tops of the studs showed the problem, some were higher than others, the one that had stuff go south was considerably high.

[JeffBoudah]

Older blocks needing retro fit roller hyd lifters need a retro fit cam with a reduced base circle.

The only reason to run the reduced base circle is to run the OEM style spider and dog-bone set-up. Just use link bar lifters and standard roller cam for older blocks with short lifter bores.

If the block has the bosses cast where the tapped holes are for the spider hold down it was cast with taller bores.

[tikitiki65]

http://www.nloc.net/vbforum/showthre.../229568-Intake

[turbo2256b]

i RECOMEND 7/16 rocker studs

How much for the GT40 heads

One of the issues with roller rockers is the rocker dosent rotate 360* just back and forth which causes the wear to the trunion and the rollers.