SPACECITY

iTrader: (1)

in a comparison to both, are they equal in flow, or do the VORTEC
outflow the lt1 heads. I hear these vortec heads are suppose to
be awesome for perfromance use. Anybody have any idea??

blkchevyz

i thought the vortec heads are designed off of the lt1 just made for standard sbc... not reverse cooled.

blkchevyz

damn someone talking good about lt1s

SPACECITY

iTrader: (1)

WOW, thanks BLKCHEVY

engineermike

That doesn't sound right at all. . . I've seen stock LT1 castings flow 190 cfm and stock Vortec castings flow 235 cfm. That's a pretty big difference if you ask me. I think the Vortec's might be closer to LT4 numbers.

Now I'd like to convert some Large-port Vortec's over to use on my LT1, mainly for the reduced timing requirement. I could run more boost on pump gas if I made optimum power at 28 deg timing.

Mike

Speed Density

iTrader: (38)

Were can you get Vortech heads from?

buffman

iTrader: (9)

Hmm 235 cfm looks mighty close to this LT1 Cast iron heads that had 20k on them

FLOW @ 28" H2O
Stock:
Lift -- Intake -- Exhaust
0.100 -- 69.8 -- 53.9 -- 77%
0.200 -- 138.5 -- 112.5 -- 81%
0.300 -- 195.9 -- 148.0 -- 76%
0.400 -- 231.0 -- 159.0 -- 69%
0.500 -- 232.2 -- 161.6 -- 70%
0.600 -- 236.6 -- 165.8 -- 70%

These are the published numbers in an older car craft for the Vortec Heads

Lift I (cfm) E (cfm)
0.200 127 98
0.300 185 137
0.400 217 153
0.500 224 157
0.600 228 158

you really have to flow bench them on the same flow bench to be able to compare them

http://www.chevyhiperformance.com/howto/97458/

also note a small and a large port size Vortec head are available.....185cc and 215cc intake ports respectively

engineermike

Another point worth noting is that the Vortec heads (large and small port) have raised runners, whereas the LT1's are in the standard location.

thesoundandthefury

iTrader: (3)

There was a post about this on camaroz28.com, and I posted the dyno #'s for a "Fast Burn" head, (which is the successor to the Vortec), vs. an LT1 head:

http://web.camaross.com/forums/showp...72&postcount=6

Then another guy pointed out that the flow #'s in that chart were for a set of prototype heads. The actual head flow #'s can be found here:

http://www.sallee-chevrolet.com/fram...der_Heads.html

According to this link, the same company got 430hp/430tq out of a Hotcam with the production, (lower flowing) heads straight out of the box:

http://www.sallee-chevrolet.com/fram...der_Heads.html

I wonder what the power output would have been if the heads would have been ported to flow the same as the prototype model? (275/int 193/exh)

engineermike

Wow! Those numbers are VERY dissappointing for a 210 cc head. That sure explains a turd we had on the dyno a few months back. . .

I hope the new Vortec large-port (206 cc) isn't that bad. They're advertised to flow around 270 on the intake.

http://www.chevyhiperformance.com/te...er/index1.html

thesoundandthefury

iTrader: (3)

What was it?

engineermike

I don't remember all the details, but I think it was a 383, FastBurn heads, 230-ish hydraulic roller, 9/1 compression, carbureted, etc. . . It barely broke 350 hp on an engine dyno. We were expecting 450+.

6 spd LT1

im sure that the 9:1 comp didnt help. what do you think it would have put down with say 12:1?

anthony

SPACECITY

iTrader: (1)

I agree 100%