LM7 Block, 243 Heads
Thread Starter
Teching In
Joined: Nov 2016
Posts: 16
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LM7 Block, 243 Heads alright guys, this is my first post so don't bash too much but I definitely need help.
a little back story on the car. I purchased a "98 SS" a couple years ago. I'm now in the process of a cam swap since a lifter went bad. figured why not. while in this process I discovered it had 706 heads on it. Figured what the heck a little bump in compression never hurt anybody. Upon further digging I found out the motor was swapped to a LM7 5.3.
Pissed off and depressed I took the heads off to send to the shop to have resurfaced and tested, and theyre cracked, so now I'm sitting with my car tore apart and debating on downing a bottle of sleeping pills lolol jk
so now I think I got a little over zealous and purchased a set of 243 heads that were off of a GTO, the guy didn't know the year(he bought them from someone). Ive been reading and basically need to know straight up if these heads are going to work or not. Ive been seeing people say to mill the heads, ive been seeing people say ill be fine. It has dished pistons. I bought a 224r .600/.600 112 cam, new lifters, 7.40 pushrods, new springs, I believe the head gasket is .051 mls. will I have issues? do I need thinner head gaskets? somebody please help.
a little back story on the car. I purchased a "98 SS" a couple years ago. I'm now in the process of a cam swap since a lifter went bad. figured why not. while in this process I discovered it had 706 heads on it. Figured what the heck a little bump in compression never hurt anybody. Upon further digging I found out the motor was swapped to a LM7 5.3.
Pissed off and depressed I took the heads off to send to the shop to have resurfaced and tested, and theyre cracked, so now I'm sitting with my car tore apart and debating on downing a bottle of sleeping pills lolol jkso now I think I got a little over zealous and purchased a set of 243 heads that were off of a GTO, the guy didn't know the year(he bought them from someone). Ive been reading and basically need to know straight up if these heads are going to work or not. Ive been seeing people say to mill the heads, ive been seeing people say ill be fine. It has dished pistons. I bought a 224r .600/.600 112 cam, new lifters, 7.40 pushrods, new springs, I believe the head gasket is .051 mls. will I have issues? do I need thinner head gaskets? somebody please help.
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Teching In
Joined: Nov 2016
Posts: 16
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so pretty much what youre telling me is that i dont need to worry about clearance regardless if i get them milled and get the thinner gasket?
i was wanting to mill them and get the gasket for the CR so it wouldnt be like a slug.
i was wanting to mill them and get the gasket for the CR so it wouldnt be like a slug.
Teching In
Joined: Nov 2019
Posts: 4
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im Building the Same Motor with almost the same specs as above. But my question is push rods !
TECH Addict
Joined: Dec 2017
Posts: 2,180
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The answer is MEASURE!!!
Doesn't matter what anybody else came up with in their build. They're all DIFFERENT, once they're not factory stock.
MEASURE MEASURE MEASURE MEASURE MEASURE MEASURE MEASURE. It's the ONLY way you'll be assured of getting it right.
Doesn't matter what anybody else came up with in their build. They're all DIFFERENT, once they're not factory stock.
MEASURE MEASURE MEASURE MEASURE MEASURE MEASURE MEASURE. It's the ONLY way you'll be assured of getting it right.
Teching In
Joined: Nov 2019
Posts: 4
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ok 10/4. 243 heads Milled .20 , mild cam , ls6 springs, truck intake. Summit ls1 Head gaskets. Ls7 lifters 0.80 wall push rods high volume oil pump. Vengeance tune. Thinking of the ls1 intake and injectors. Long tube headers. Should make decent power ?
