Chevyman5436

I got a friend of mine who is looking to pull a junkyard 5.7 vortec out of a chevy truck and put it in his fox body mustang. He is keeping it a stock long block I believe, is there any casting number or year 5.7 that is more desired for performance build? Do some of them have different head castings, possibly different pistons? Are there any other "stock performance" preferred GEN 1 sbc's that can be pulled out of silverados or caprices that are good for light performance mods?

Chevyman5436

Anyone?

kendogg

iTrader: (2)

Nope. They're relatively the same from '96-2000 (or '01 maybe in the Express Vans, forget what year theys topped running them). There were a few PCM differences from 96-97, then 98-99, then '00-01.

Notalent

The roller block is whats desired and that will be found in 1996-2000 Trucks/Vans and has a better EFI system.

1987-1995 is the non roller block and has the TBI Injection...which sucks.

You can also find the roller blocks in 1987+ Camaros/Corvettes.

87silverbullet

iTrader: (11)

87-95 weren't vortecs anyway.

Don't forget the firebirds too.

One question, why not put a 5.3 truck motor in the car? You can get them for $500 all day long

kendogg

iTrader: (2)

Right. Plus the Vortec blocks are single piece rear main and 4-bolt main blocks. 'Better EFI' is relative though, I wouldn't consider the stupid spider injection setup 'better'. The Vortecs certainly make more power in stock form than a TBI motor, but both the fuel & ignition systems are ****. I also agree - if you haven't bought a motor yet, just get a 5.3. Superior in almost every way. Only reason I'm building my Vortec is because it's whats in my truck, and I already have it.

87silverbullet

iTrader: (11)

Yes they were 1 piece rears but not all were 4 bolt. I remember doing the TSB for rear main bearing clearance at the dealership on my dad's friend's 1998 tahoe and it was 2 bolt. 1986 started the 1 piece rear main seal thing on T/B motors too.

The spider stuff wasn't that bad unless people ran shitty gas. It was better that the T/B stuff by light years. You could tune it like an LS1 unlike a T/B setup. The only issue was that it was hard to get bigger injectors for them plus the regulator was built into the intake. Most guys changed it for a carb style efi intake so they could run normal injectors. My buddy had ported heads on his truck with a 232/236 cam in his truck with the EFI. You couldn't even think about running a cam like that with T/B injection.

kendogg

iTrader: (2)

Interesting, thats good info to have. Are you, or were you, a dealer tech I presume? I'm doing a COP/Multiport conversion on mine shortly, I think it's definitely the right way to 'fix' it if you own one, but like others said, if you don't already own one - no reason not to just skip it altogether and get a 5.3 instead.

big hammer

I think 1\2 tons had slightly better flowing heads.

kendogg

iTrader: (2)

????

This is news. Supposedly, there were only 2 casting numbers of Vortec heads, and 95% of all of them got the one casting number, I wanna say 906 was that number, I think??

87silverbullet

iTrader: (11)

No, big hammer is right. The 3/4 ton trucks had a different valve seat that restricted flow compared to the 1/2 ton trucks. Nothing a valve seat change couldn't cure but there were so many 1/2 ton trucks why even bother changing seats and all when the 1/2 tons were a dime a dozen.

kendogg

iTrader: (2)

Thats crazy, I had no idea. I'm assuming we aren't talking about much difference in flow though, right? I'm guessing since mine is a tow rig, work truck, keeping the bigger HD seat would be a good thing, right??

87silverbullet

iTrader: (11)

It will hurt performance but the heavy duty seat was for the durability factor. So you have to choose for what you want. I would just use the regular seat heads.

Notalent

Eh,...most of this was mumbo jumbo. 1/2 ton vs 3/4 had nothing to do with it...just certain batches of the 906 heads and the exhaust seat insert (most didnt) and its not big deal. You can smoothen the lip very quickly and its common to do so. At the power level most people are looking to make with these heads, it will not matter either way really.

Now if you jump to the castings.... The Early 906 and 062 CANADA castings are the more sought out after heads and flow better (about 20cfm) than the later 062 Mexico heads. I have a 350 Vortec build I do that I rate at 350HP/400TQ.... I know with the Mexico Head it will make just over that 350HP, when I get a Canada head I will see 365+Hp all day long. I have seen this on the dyno with different combination more than 100 times.