can somone please educate me??

[mattjones]

I found some 243 heads that I'm gonna use with my cam hopefully that will help?

[kerrige]

If you swap to those heads direct you will lose some compression. You need to swap to 4.8 pistons or mill those heads to make it worth it.

[mattjones]

If you swap to those heads direct you will lose some compression. You need to swap to 4.8 pistons or mill those heads to make it worth it.

The company that's selling them said they have been milled down to keep the cr the same and ensure a clean mounting surface

[kerrige]

That should work nicely then. Who are you getting them from and how much do they claim to mill them?

[mattjones]

That should work nicely then. Who are you getting them from and how much do they claim to mill them?

It's a company off eBay with the username synergyss (180) he's got a 100% feedback since 1999 and he said that the deck surfaces are milled slightly. Here's the link http://item.mobileweb.ebay.com/viewitem?itemId=221150463739&index=0&nav=SEARCH&ni d=56469522584 maybe you guys could throw some input in before I bid on them???

[pl4yboy]

It's a company off eBay with the username synergyss (180) he's got a 100% feedback since 1999 and he said that the deck surfaces are milled slightly. Here's the link http://item.mobileweb.ebay.com/viewitem?itemId=221150463739&index=0&nav=SEARCH&ni d=56469522584 maybe you guys could throw some input in before I bid on them???

How much is slightly? A surfacing to make sure they are flat, or .030? Makes a big big difference when it comes to both compression and ptv clearance. You could demolish that motor the first time you turn it over if you don't know.

[mattjones]

How much is slightly? A surfacing to make sure they are flat, or .030? Makes a big big difference when it comes to both compression and ptv clearance. You could demolish that motor the first time you turn it over if you don't know.

Ill have to contact the seller about them or maybe I should just find some 243 off an 05 silverado because wouldn't they be ok considering they came off a 5.3 as far as clearances go?

[bangbangskeetskeet]

243's didnt come on the trucks until 07.. And when you toss a set of stock 243's on a stock 05 5.3 your going to lose a bit of compression. If youre looking for something you can just toss on get some 862's of 706's and have them ported.

[Frenchy]

243's didnt come on the trucks until 07.. And when you toss a set of stock 243's on a stock 05 5.3 your going to lose a bit of compression. If youre looking for something you can just toss on get some 862's of 706's and have them ported.

L33's came with them in the form of 799's. Exact same head different casting number. They had flat top pistons though. To the OP, I'm running 243's milled .030 with a .598 lift cam. No issues.

[bangbangskeetskeet]

L33's came with them in the form of 799's. Exact same head different casting number. They had flat top pistons though. To the OP, I'm running 243's milled .030 with a .598 lift cam. No issues.

I was under the impression that they were flat tops with 862's still not the 799/243's?
Guess you learn something new every day.