SheldonZ28

iTrader: (4)

Hey Everyone.

Ive got a set of 716 casting 5.3L w/ a bowl blend done on them.

Trying to determine if i should use these heads or go for some 241 castings.

Here's my motor spec's:
'99 LS1 shortblock
TR230 cam
Stainlessworks LT headers
LS6 intake

Im trying to make the car a good cruiser, make about 380+ Rwhp, and get some decent fuel milage.

Ive got the 5.3 heads now, is it worth selling them to go for 241 castings? I really dont want to buy any CNC heads, or LS6 heads.

If it means ill make 380rwhp w/ the 5.3l and 385 w/ the 241 heads i wont bother, but if its a 10+ rwhp difference, then i might as well

All help greatly appreciated.

Sales4@Texas-Speed

iTrader: (4)

I would not expect to see more then 5-10hp from a swap like that. The nice thing about the 5.3l heads is they will have a smaller combustion chamber which will give you more compression yielding more torque.

DONAIMIAN

iTrader: (18)

Are the stock size valves still in the 5.3's?

Beaflag VonRathburg

iTrader: (176)

I'd use the 5.3 heads, have them milled as much as you can get away with before having to flycut ($50), and cut for 2.00 / 1.55 valves ($24). That way you can use the stock valves out of a set of LS1 heads that you could probably get for $25-50 depending on your shopping ability. That'll let you work with what you have and work well on a budget.

SheldonZ28

iTrader: (4)

I dont think id want to mill them, but would my machine shop just cut my current valve seats for the new valves?

If its only going to cost me $100 to have the bigger valves in my 5.3L heads and i would have higher compression so more tq. then id definately be willing

Beaflag VonRathburg

iTrader: (176)

^ Why would you not want to mill them? That's just giving up power. Yes, stock 5.3 seats will go out to 2.00 / 1.55 and they'll give you an increase in flow.