02bluess

iTrader: (18)

In the middle of installing some TEA 1.5's, and I've got a couple of easy (I hope) questions.

(1) The TEA's have Comp 987 dual springs installed; will these work with my stock rockers? They look a lot bigger than the old Comp 918's I was running; just want to make sure there won't be any clearance issues.

(2) I bought the heads from Texas Speed, and Trevor indicated in his post that the heads had been cut .030". Based on that, I went ahead and ordered a set of new hardened 7.350 pushrods to replace my 7.400's. Does that sound right? How could I go about checking to make sure? I'm using jmX's website to help me through, but the only think I could find was that milled heads may require the 7.350 pushrods.

Thanks in advance for any info y'all can provide.

SeeinRed

I know the pushrods are correct, so you're set on that unless i'm wrong. But as for the springs, i'm not sure.

Mike

haole_boySS

iTrader: (1)

The stock rockers will work fine with the comp 987's. As far as the pushrods, you should only need to shorten them if you are running a high lift cam. If the lift is over .580 then its probably a good idea to use the 7.35 pushrods.

02bluess

iTrader: (18)

Specs on my cam are 230/224 .575/.563 111LSA... Would there be harm in going to the 7.35's, or should I stick with the 7.40's??

Is there a way to measure which would be appropriate that I could accomplish in my garage??

BTW, thanks for the info so far!

Paul...

jmX

1) It all depends on the retainer. There are some retainer designs that when used with a 987 won't clear the stock rocker. Most LS1 shops seem to use the flat style now that clear with no issues.

2) With a cam that has lift like yours, the basecircle on the cam will be smaller which sinks the pushrod down a little. That will compensate for the milled heads, so 7.400's are probably fine in your case. 7.350's may or may not be too short...those would probably be right on the edge of not working and you wouldnt have much (if any) preload on the lifters, you'd have to just check and see. Personally I'd just throw 7.400's in and be done.

Tin Indian

You have mail ...

I don't know exactly what the base circle of that cam is. You can measure it
with a mic. Measure across the lobe. This will be the shortest distance on
the cam. Then cut that number in half. That distance will then be the cam's
"centerline to lobe heel" distance. That's the number you are concerned with.

You will find that the base circle is 1.552" on a stock LS1 cam. Again, you
will need to cut this distance in half in order to get the cams "centerline
to lobe heel" distance. The stock LS1 cam has a .776" centerline to lobe
heel distance

Do this for both the stock and aftermarket cam. I will bet that the
aftermarket cam's centerline to lobe heel distance is about .030" smaller
than the stock cam. I attached a picture showing exactly what I am talking
about.

The stock cam centerline to lobe heal distance is .776" and uses a 7.385"
pushrod. If the aftermarket cam has a .030" smaller cam centerline to lobe heal distance,
then you would need a pushrod that is .030" longer than stock.
That would then be 7.385 + .030" = 7.415"

If you mill the heads .030", that would require a pushrod that is .030" shorter.
That would be 7.415" - .030" = 7.385" (stock length)

As you can see, it then becomes just "Tit for Tat".

02bluess

iTrader: (18)

Thanks, jmX! BTW, your site is great!! I've used it for pretty much everything I've installed/done so far!!

So you're thinking that I could just throw the 7.400's in and forget it without having too high a preload?

This is probably a stupid question, but when you say just "check and see", how would I go about doing that?

Thanks again for everyone's help

Paul...

02bluess

iTrader: (18)

Thanks for the response, Tin Indian!! That's exactly the type of information I was looking for!!

Since it sounds like it's six of one and a half dozen of the other, I think I'll just go ahead and use the 7.400's; that's what I'd been using with the 230/224 on stock heads, anyway.

Thanks again for everyone's help!! Don't know where I'd be without LS1Tech, although I guess maybe I'd still have the money I've been spending on parts



Paul...

TaTommyWS6

You can use a caliper like the one below to check.

Tommy