This was what I remembered reading in car mags back in the 70's,but maybe this isnt the case.It was because of this that I was rather dissapointed when I recently dynoed my 468,because I was hoping for over 600 HP,but it really produced 550 HP.Understood Sir.
I have always heard that SS motors were underated by the factory. If that was the case.... The LS6 was factory rated at 450. What was the real horsepower rating???? I think I read something like 500 somewhere.:beers:
First I know the Armstrongs, and yes they do set records. 50 grams is a lot of weight to get rid of, but you also forgot the weight of the pins, which the SRP is lighter, any time you take weight out of the bottom end your HP per second goes up, as with reliability. Now as far as piston to valve clearance goes we used those pistons before speedpro decided it would be a good ideal to send the manufacturing plant over to india, every combination of big block we built, we had to flycut those pistons, so I could see where Gary came up with this notion. When speed pro sent the plant to india thats when I stoped buying their pistons, and believe me we had to modify alot on those pistons to use them in my engines, so beware of india made speedpro pistons. MWith all due respect to Gary and his supposed engine building talents,I have something to add here.It would seem to me that he has a hate on,or is very shortsighted,when it comes to SpeedPro/TRW pistons.On more than one ocassion he has told me that the 2465 would NOT WORK with my combo,there was no way there would be enough piston to valve clearance.Well,after degreeing the cam in,and claying each piston and checking clearances FOUR times,the minimum intake clearance was over 0.125,and the minimum exhaust clearance was over 0.200.So guess what Gary,you were wrong !!.He also told me how heavy they are.These pistons weigh 690 grams,a comparable off the shelf SRP 21236 weighs 638 grams,this is a difference of 52 grams.Sound like a lot ? Well,according to my wifes kitchen scale,a dinner fork weighs in at app. 40 grams,and a tablespoon weighs in at app. 50 grams,so this probably doesent amount to anything in a street driven car with a rev limit of 6500 RPM.So now he says that a different ring package is worth 30 horsepower in a combo such as mine?? Lets get real,this is ridiculous,he must be getting his numbers from a car magazine with inflated dyno numbers.I had asked Allyn & John Armstrong at the performance shop about this,and Allyn told me that they have played around with different weight pistons and different ring packages,and in a street combo,the difference is negligable,certainly not the 30 HP that Gary quotes.And you may well ask,who is Allyn & John Armstrong,ask anyone who races in IHRA & NHRA along the Eastern seaboard in Comp Eliminator & Super Stock classes,and they will tell you that these gentlemen from little old Nova Scotia Canada are well respected,and record holding,drag racers.You could also ask the former owner of the Mr Gasket group of companies who builds his race engines.Is it Gary's company ?? No,its A&J Armstrong,world renowned engine builders
Heres a PS:
Gary I get the feeling that you are an ignorant and narrow minded person,and being from New York makes you think that you are smarter and know more than anyone else.But you dont really.Well,heres something for you from Nova Scotia Canada :
BITE ME !!!!
Gary,as always thanks for your insight and experiences :thumbsup:
Thanks, guy's!!Gary,i second what Chris said.
Thanks a lot for your experieced input,we all learn a lot from you along with a few other good engine builder/machinests that are willing to help us out here in team chevelle.
Watch it on that internal 454 thing, I make my living on thoseThanks, guy's!!
Mr. Guy, sir, just to set the record straight here, you "don't kill the messenger because you don't like the message"!! You were the one stating, and I quote here, "wasn't real happy with the HP numbers, expected 600 or so"??
Well I would just ask "exactly who do you blame for the numbers"? I most certainly DID NOT pick your pieces! Mark above raised a valid point about TRW slugs being more or less "NOT a real good first choice". I actually have customers here that might trade their first-born to get 50 grams out of the reciprocating numbers. To be really honest here, I would avoid an external (454") build unless it was in "judged" car show!
I don't know your total "monies spent" (don't really want to know) but I can tell you based on my experience you should have maybe 700 HP+!
Not sure if you or "your guys" picked the L2465's that were designed around a 2.065" intake with the "pressed wrist pins", the 5/64", 5/64", 3/16" ring pack (not a choice here with those slugs), no pin-oiling, and not even the best material for a piston anymore. EVERY point mentioned here is a
"negative" when looking for HP and E.T.'s. Let that blame lay where it may!!
(Add) But, I do "love" the analogy with the "kitchen utensils" though!!
Thanks, Gary in N.Y.
P.S. With all the good "high-dollar" parts you have, Brodix heads, Isky rollers, Comp springs, for the life of me I can't "see" TRW "press-pin" slugs in the program under any circumstances! Re-read (slowly) the P.S. in my original post, it's self-explanatory AND to the point!!
Double P.S. You can go back and read my answer to you on the "Speedtalk" forum, there was no mention of the pistons "not working at all", only of a POSSIBLE conflict in the 2.250" valve and the 2.065" valve pocket!!
I saw an episode on speed channel's "American Muscle Car" where they dyno tested several factory motors like a Chevy 409, Ford 427 and a 426 Hemi. The Hemi was well in excess of the rated 440 HP numbers from the factory. The Ford 427 was also much higher than factory rated. It was pretty interesting to see how those factory motors performed, assuming that they were definitely factory correct. If you have speed channel keep a look out for the show. They also had one epsiode that tested 5 factory muscle cars in 1/4 mile, slalom, braking and other stuff. A 70 Chevelle 454 was one of the test cars along with a 427 COPO Camaro, Boss 429 Mustang, 426 Hemi Mopar, Buick GS and a 70 GTO with a RA IV 400. The GTO pretty much outperformed them in almost every category.Gents,
I was wondering about the real horse power ratings on the 1970 454's. Does anyone know what they really were putting out?:beers:
I guess that makes sense because the Hemi came up over 700 HP I think? Seemed odd. I also seem to remember that the Ford 427 was a race only version?That epsiode has been discussed plenty of times here and the Ford and hemi where NOT factory stock..if you go back "in time" and look up the road tests of the day for any of those hemi or 427 Ford cars the HP numbers from their trap speed/weight do not match the HP numbers from that episode of American Muscle