I was just wondering in GM's over the counter iron heads what the difference was between the LS6 and LS7 rectangluar heads that were offered.
Thanks

Somebody else correct me if I'm wrong, but I
think they may have the same head.Different piston
and cam.Just a guess though.

The 12.5 piston in the LS-7.

So basically the heads were the same ?
Any idea what size valves the LS7 head had ? was it 2.25 or 2.30

Thanks

Pretty sure, just basic rec ports with 2.19/1.88's

70 LS-6 is a closed chamber The LS-7 is open chamber. Same size valves in both heads. Some of the crate LS-6s used open chamber heads to lower compression when the gas got bad.

LS-6 was closed chamber in '70 and open chamber in '71. We should have established the distinction between the model years.
'70 LS-6 11.0/1 closed chambers Rec. Solid CAM
454/450hp
'71 LS-6 9.01 open chambers Recs, Solid Cam
454/425HP
LS-7 12.5 open chambers Recs, Solid cam
454/465HP (rated at what 5200 RPM?, when was the last time you saw a 454 12.51 motor peak that low}
Does anybody know what the actual power output of the LS-7 was? In fact, didn't the LS-7 have the L88 cam?

No Sir, it had the .600 lift puppy in it, the ZL1 cam. L88 cam was only 560/580. I dont have the durations numbers. Have heard that the L88 did 560HP at 6500, heard......

Either way, hell of a ride on 7" wide Bias Ply Tires! And the best part, everybody that had an LS-6 ran it like the way they were meant to run. Can honestly say, I don't think I ever really ran into someone that had done a real LS-7 install on the street. Do remember getting a ride in a L88 in a '69 Vette Cnv - think that's when I got the first sign of a receding hairline - from the high pressure wind blowing over the windshield!
How many of us would jump at the chance to run down to the local Chevy dealer, browse around and then labor over whether to get the 350, 375, or 425 HP option, with either the wide ratio or maybe the close ratio or do I make it a mama's car and get the automatic? "What about air conditioning - I don't want air conditioning, air conditioning's not for racing - eats waaaay tooo much power".
Decisions, decisions.

GRN69, vivdly recall the old L88 bolted into my buddies 67 Camaro, those M50-15s, 4 speed. We had hollowed out the mani, so it was even slower to build power

first 'beat run', he stands on it, it start to pull and then at around 5500 rpms, the tires just went up in smoke!

Easy to float a motor like that!

Wasn't a real LS-7 with good four tube, long headers good for like 600 hp??

AND the only higher hp motor was a full house MOPAR Hemi or possibly the 427 "Cammer" Ford??

Not wanting to start a contest, but rather just curious, that's all...

pdq67

I vaguely remember an article in one the Mags of the day (circa 70 - 72?) took a big block Vette, dropped in an LS-7 and went to the track. The article closed with the Vette being hauled off with a blown rear. Other than that, my only experience was a '67 SSJA Chevelle that we bought and converted to brackets around 1980 that we dropped in a 12.5/1 454 motor consisting of a barage of used/mixed parts. Once we played with it, it did drop into the 10's, but we were young and ran out of money long before we ever got consistent enough to do any real racing. Never did have anything like that on the street though. Irony is how things change. In the 70's Sunoco had 100 Octane at the pump for maybe 25 -30% premium price - a 450HP motor was considered a high ouput street motor. Today, your lucky to get 93 Octane - 450HP is almost run of the mill.