king of the wood

Hello everyone!

So here is my dilemma. I have a 5.3L LM7 engine that I am starting to rebuild (first ls rebuild) and I am trying to figure out the set up for myself. I would like to push somewhere between 450-500 hp once im done. But not sure on my heads choices. I would like to keep the stock (to save a lil cash) and p&p them with new valves, new springs etc. Below I have listed what I have thought about so far. *I have not started this project yet*

Here is what I plan to do:
-5.3L LM7 Engine
-New bore 4.030
-Stock Stroke: 3.62
-Eagle I Beam Rods (6.125")
-Mahle Pro Packs
-Texas Speed 224r cam with 112 lsa
-either keep my 862's and port & polish them or upgrade to 243's. I know I may lose compr with the 243's but can I just have them milled to keep a high c/r?
-Patriot dual gold springs (max lift .650)
-Edel VJ Intake (dual plane) with MSD 6010
-Holley 750cfm
-not quite sure on the HEADERS size yet


so my major issue is with the HEADS. I have read mixed reviews on the 862's and the 243's. I would like to just get the best bang for my buck. What suggestions do you all have on worked 862's vs stock 243's? Can I have the 862's worked to match the 243's? will that be more or less $$?

Thanks in advance.

godlyxdan

iTrader: (1)

Dont do a 4" bore on this block, highest you should go is 3.905
As for the heads I would just get the 862's worked, whats the budget look like?

king of the wood

No 4" bore? Please enlighten me. my budget will be between $200-$500 as I am in no rush to finish this.

godlyxdan

iTrader: (1)

minimum wall thickness on these will not allow for a safe 4" bore
with only 2-500$ i would definitely stick with the 862's

I'm currently building my own LM7 to go in my Blazer so im right here with you on the "no rush" part, im taking all winter on mine

king of the wood

Yup your right. I just did a short research and the walls are waaay to thin for that bore. wheeew, I'm glad I posted this first. Now as far as the 862's go. I called a local shop near my house and asked for a quote for the p&p, the guy said he needs all the specs that I am looking for. Not exactly sure what is the best set up for the 862's and that engine. Any suggestions? Yes, I will be taking all winter as well as I don't physically have a car to put it in yet but looking towards a 79-87 El Camino. Not looking to drag (YET) lol but just something to build with my son.

king of the wood

He also said, he needs the thickness of the gaskets I will be using. after research I found .040 would be ok or .051.

godlyxdan

iTrader: (1)

Not really sure how much you would need to do them, they really are good heads, high compression with a pretty small chamber. Just go through and refresh them and they should work fine for your application as is

Not to sound sentimental but I wish I had a dad willing to do this with me, im only 18 with a father who has been in the racing industry since he was my age (30+ years) and he doesnt have any interest in helping, it means a lot that this is a father son thing

king of the wood

Hey now worries kiddo. My father was the same way and now he is gone. passed away in 2005. Left me with none of the cars he built. so I know where your coming from. Stick in there as he will realize and wake up one day.

Thanks for the info.

godlyxdan

iTrader: (1)

Thanks a lot, I sure hope he does!!!

But going back to your heads, it seems people get pretty good results out of larger valves with minor port work done, Idk exact numbers but that might help narrow down the numbers youre looking for