k24556

I'm in the process of gathering parts for a winter mod project on my 2000 FRC 'Vette. My plan is to add LS6 heads, a cam, LS6 intake and headers.

I located some heads, but the previous owner has installed 3/8-16 inserts for the rocker bolts, so in order to use OEM rockers, I either need to get the inserts replaced back to 8-1.25 or get the trunnion bores of the rockers reamed to clear this larger bolt.

Looking for advice on this. what is the thought about these two ideas, or is there a third option.

Thanks, in advance.

usdmholden

If it has 3/8-16 inserts it was most likely to convert the heads to stud mount rockers instead of the OEM pedestals. Otherwise I see no reason to install the inserts.

Alternately, if they did a good job, it allows you to run stud mount rockers, assuming the work was not hacked together.

Simple solution... buy different heads.

k24556

you are correct on the reason for the conversion. But as life is, I now own the heads and am trying to get back to "normal".

usdmholden

Then what I would do is call a company that makes rocker arms for both pedestal mount LS engines, and older stud mount engines (SBC / BBC / SBF / whatever) and explain to them what you have and let them recommend what you should run based on the lengths of the cup to the pivot and the tip to the pivot.

Just because older 1.7 ratio stud rockers are the same ratio as 1.7 pedestal rockers, it does not mean the distances between pivots and cup and pivot and tip are the same.

Alternatively, I'm sure there are valvetrain experts you can ask and get a good answer, from my experience working with Brian Tooley and Ed Curtis long ago, they are probably the guys I would call first, and then order what is recommended.

This is all assuming that the stud mount inserts are installed in the same place as the pedestal mount holes were.

usdmholden

OK, so I was curious and did a search on google.

Comp Cams makes a conversion to do specifically what your heads are converted to do.
http://texas-speed.com/p-1218-comp-c...r-arm-kit.aspx

Comp p/n 1370-16 (1.85 ratio) and 1375-16 (1.75 ratio).

k24556

Thanks for the response. I was hoping to use the stock rockers in some fashion, so I was looking for ideas to salvage this set of heads and return them to either a thread of 8-1.25, or find out if I can ream the trunnions to 3/8 dia. I have a contact into Comp cams and will keep all posted as to what they might say about reaming their trunnions.