What do each of them flow stock and what do each of them flow when ported..

and im talking about a port job from a reasonable priced head porter.. ie. Llyod Elliot

 

They are ALL over the board. LS1's will outflow LTxs no matter what.

A really good LT1 will do 270ish on the intake 260-265 is very good.

A really good LT4 will do 290 ish on the intake, 275-285 is usually seen.

LS1's are capable of 330+

And as always its hard to compare flow numbers because of the enormous amount of variables in benches.

Llyod Eliot does do good heads.

 

thanks for the info..

wow i didnt know ls1s flowed so well.. i thought they were in the low 300s...

 

The best LT1 stuff will usually peak in the higher 27Xcfm range on the internet, and the same in real life. 99.9% of it peaks in the 25X range IRL . Consider you can make up to around 500hp with a HR cam and 270cfm... and almost noone gets close to that.. so maybe something is up

LT4 stuff.. most that I've gotten from other places peaks in the 260-280 range. If you're lucky 280-285. To sit and eek more out of it, you'll usually end up in the 29X with a 2.02 valve.

LS1 stuff isn't going to flow 330, more like around 300 with a 2.02 valve. The 6L truck stuff will get near that with a big valve but the regular ls1 stuff wont. Of course everyone claims that, but again.. the only one I've ever had get over 280cfm was a mandatory cnc head from Lingenfelter. It was huge, but it flowed well .

If you're looking for cheap stuff b/c of a budget, expect 245-255 IRL from LT1 stuff, 255-270ish for LT4 stuff, and about the same for regular LS1 stuff. Based on the heads people have sent in from all over and I've tested myself anyway .