454 Big Block Question

[Cole_lol]

Hello all,
I have a big block that I just recently broke down and on the front
were you have your timeing chain and what not there is a marking
on the block that has a big E on the left and then soemthing
that says SS Perf and under it the number 10.
What does that mean if anything at all?
Thanks,
Cole

[luxeryvic]

is it the stock engine, and wat is the engine in?

[Cole_lol]

Well, It is a engine that was pulled out of what i was told a suburban.
But I just didnt know if the markings made any diffrence about the block.
Someone told me it was an LS6 block and some others told me it didnt matter
so thats all.
Thanks For Your Help,
Cole

[MrPbody]

Those are foundry marks. Virtually all "short deck" Mark IVs (through '92 or 3) BBCs have a Hi-Perf/Pass cast into them somewhere. An LS-6 is a 4-bolt main block with a forged steel crankshaft. Not found in Suburban as original. That's the 450 HP version, found in '70 and '71, mostly Chevelles, but I've seen them in Corvette and Camaro as well.

LS-6 was also equipped with rectangular port heads, exclusively.

Jim

[72chevelleOhio]

Originally Posted by MrPbody

That's the 450 HP version, found in '70 and '71, mostly Chevelles,

You forgot the controversy of the 450 hp being underrated. (aka my favorite part! )and the '71 Chevelle LS-6 was the "little" 425 hp.

[MrPbody]

I was always under the impression it was LS-7 that was "under rated" at 460 HP, with the 12:1 compression and the big solid cam. Liie ZL-1, 500 or 550 was more accurate. LS-6 was rated at 450 and based on how many my 366 HP GTO beat, I wouldn't say it was under rated. The Ram Air III WAS under rated about 30 HP, but I would think the big Chevy would have an edge if it were more than 20 or 30 HP "bigger". The Pontiac always made up for it with bottom-end torque, which all rectangular port BBCs are hurting for. I got better runs in street "trim" from the 390 and 400 HP 427s.

Jim

[Yardogg]

Originally Posted by MrPbody

I was always under the impression it was LS-7 that was "under rated" at 460 HP, with the 12:1 compression and the big solid cam. Liie ZL-1, 500 or 550 was more accurate. LS-6 was rated at 450 and based on how many my 366 HP GTO beat, I wouldn't say it was under rated. The Ram Air III WAS under rated about 30 HP, but I would think the big Chevy would have an edge if it were more than 20 or 30 HP "bigger". The Pontiac always made up for it with bottom-end torque, which all rectangular port BBCs are hurting for. I got better runs in street "trim" from the 390 and 400 HP 427s.

Jim

LS-7 was never put in a COPO or on the assembly line, It was a crate motor only over the counter (only?). LS-6 for 71 was Corvette only (188) no Chevelle's and strange as it sounds no LS-6 70 Corvette. There were Truck four bolt main and forged crank motors but not cross drilled. The big heads were also on the L-78 396 and same with L-89 both very rare. Check the pad on the deck right side stamped and (behind the alternator) look for the "C" prefix it will tell you if it is a vingtage block . If its IS an LS-6 or even an LS-5 save it and chase down the car it'll be worth something to soeone and just enjoy it's still a 454 torque monster..

Ysardogg
PS
Some Great legendary dealer's put in anything your little heart desired.

[Yardogg]

Originally Posted by Yardogg

LS-7 was never put in a COPO or on the assembly line, It was a crate motor only over the counter (only?). LS-6 for 71 was Corvette only (188) no Chevelle's and strange as it sounds no LS-6 70 Corvette. There were Truck four bolt main and forged crank motors but not cross drilled. The big heads were also on the L-78 396 and same with L-89 both very rare. Check the pad on the deck right side stamped and (behind the alternator) look for the "C" prefix it will tell you if it is a vingtage block . If its IS an LS-6 or even an LS-5 save it and chase down the car it'll be worth something to soeone and just enjoy it's still a 454 torque monster..

Ysardogg
PS
Some Great legendary dealer's put in anything your little heart desired.

MrPbody

Come down to San Clemente and I'll help you out with big words and show how stylish the rear bumper is on my STOCK 71 SS 454 LS-5 not 6 convertible M22 4 speed fac. air, Or my up and comming built 71. I have a lot of friends with GTO'S and TA'S there great. My friend Lars is just replacing his Ram Air IV with a nice 455 (why? beacuse he can) that will be fun. I'm shure your Goat is nice but remember to pass a Chevelle like you claim the Chevelle it has to be going in the same direction. I fly Helicopters and I think I've seen Mr Peabody in his "Little Flying Saucer" (Ram Hot Air-1) Just funnin..

[chevybuel]

i have a 454 motor that is disaling and back firing can anybody help please, i had the carb rebulit put new plugs and wires and timed it at 6 degrees

[MrPbody]

Yardog,

I think you missed something in my post that's rather significant... I was talking about my street racing experience in the early 1970s... Not current. I don't own a GTO anymore (wish I DID!). Lars could have done a lot better than a 455. We (most Pontiac "builders") don't use them anymore. A 400 block with a current "stroer" kit is far "tougher" and makes the same or a little better power.

Chevybuel,

Are you sure the distributor is in correctly? What is the compression ratio? You could have a multitude of issues. Start at the beginning, and go "by the book", setting the dwell, timing and idle speed. Report back.

Jim