Nothing is absolute. What one can get away with "up north", won`t fly down here in the heat and close to sea level.

What is your cranking compression?

Sent from my SM-S901U using Tapatalk

approx 190-195


not sure who said absolute but if your talking about the 1 point he was only generalizing saying aluminum can handle more then iron

Curious: Who does the shot-peening for you? I wouldn't know who to go to for shot-peening.

Every machine shop in America does shot-blasting as a parts-cleaning deal, but shot peening is a whole 'nother matter.

there was a place in Trenton n.j. around the shop that does my drive shafts but the guy passed away its to bad he was a good dude and an encyclopedia on legs, had great stories too

And neither are going to make cast steel OEM rods "last forever".
I had the place that shot peens F-18 jet engine fans blades do a set of 455SD rods. It was not cheap and you got a test strip of metal blasted to a certain spec.
I had 1400$ into those rods.
And still they were not as strong as the 300$ generic 4340 H beams that replaced them.
I would like to see a TRW-Sealed Power forged 455 piston that has 1/16" rings. They all have 5/64 rings that I know of.

Cast iron, not cast steel. FAR too much carbon to be "steel".

Casting steel is not for sissies. Difficult and expensive. Casting iron can be done by any third-world hell-hole.

SMH...
come on dude.
when someone says last forever do you take that as it will? what he ment was they will be fine.
when someone say hey nice car look at the size of the wheels there on steroids.. are they? why are you so angry and have to be right? I'm not here to debate you or argue with you ,since your first post you've done nothing but snipe. other people are giving me input and there experience not jabs enough already your dog is bigger then mine is that what you wanted to hear?i know you have been here a long time and have people here so go troll them.

here is your 1/16 second ring:beerchug:

You asked about 11.4 and 91 octane. Some folks say yes, no problem. And, they probably have done it. I say, it depends a lot on where one is located.

Run 11.4 on cast or aluminum heads down here, on 91 octane, and you`re asking for problems.:)

The absolute wording came from advise that one can get.;)

If you were pumping 190 to 195 with the past combo, I think it would have been wise to get the 85 cc KRE D ports. The 74 is going to be pushing things with only a very small gain in power.

Location, temp, and elevation makes a big difference. The engine ran before and has a baseline to go off of, I don’t know why the builder decided it is wise to push the compression that much higher. I am a high compression guy, more than most, but I would not have went with the 74 cc versions, 85 cc would have been a better choice. After you try the 74s report back here and tell us how it’s working.:D

The SD-455 replacement TRW pistons use 1/16 top rings and some of their dome piston offerings for the 400 & 455's use them.


A lot of shops have actual shot peening equipment. They used to be somewhat common in performance machine shops and do a good job.
You just don't get an Almen strip or FAA certification.We used to have Curtis Wright Industries shot peen a lot of cranks and rods for us. It was $150 to peen eleven rods or one crankshaft in the early 90's. I can't imagine what it would be today.

Yup!

Just for the record here is the TRW dome piston for the 455 with either SD or HO heads that made use of 1/16” rings in both grooves.

Excuse the tilt!

You are right, Arma Steel is just a good quality cast iron.
OK, you know something about casting steel. I have always wondered why heads could not be cast in steel vs iron.
They would be a lot easier to modify-weld if they were in steel. I have welded a ton of cast steel and its very easy compared to iron.
Is trying to cast steel into something as intricate as a cylinder head a no go ?
There has to be a reason its not done. It would solve a lot of repair problems.

You came here asking for help. So I ran a TRW 455 for about 30 years and pushed it about as far as I could at 9-1 CR. Got down in the 10s. Now just built a 11.5-1 engine with aluminum heads so there is a comparison to what you are trying to do. Only I have safety margin on top of safety margin and even that is no guarantee of anything.
Post #4 is trying to tell you, and post #5, and post #7, post # 8( might want to listen to him) and post #9.
Its like you are trying to build a engine with a glass jaw and the price could be a hole through the side of your block.
Engines are very expensive and PMD blocks are not made anymore. Not to mention your time which plays into this.
A safety margin should be a part of any street-strip build and all it would take is a bad batch of gas with what you are trying to do and its all over.
Cast rods should not be a part of any semi serious build.
I have a 455 block out in my garage and I picked it up from a kid who tried to race it at our track. Kept the RPM low and had a smaller cam than yours.
I told him the same thing, ditch the cast rods. He did not take the advice and stacked the bearings when those cast rods egg shaped.
He was about 2 seconds from snapping that rod and ruining the block. The crank is junk.
Not sure where you get the angry part of what I am trying to say. I can be blunt, its not personal.
The 1/16 ring comment was mostly about being able to get a good ring pack and TRW pistons-pins are heavy. And you are slinging them on cast rods. That 1/16 2nd ring is not helping your situation.

People here are just trying to advise you not to build a potential ping monster with cast rods.
Good luck with your build.

Jay,
not sure what the last motor was ,the 190-195 will be the new set up as per the "cranking pressure calc" I'll know for sure in a week or so.
SO getting back to the original question.
" 11.4:1 "
i did a lot of reading and some math to figure out what the 2 big Pontiac shops and my builder were trying to tell me. ( tried to use a forum and take the easy way out)
has anyone looked at the cam card?
with the intake closing @ .050 73 ABDC she will not start make pressure until late in the compression stoke so it needs a higher compression to take up the slack in the low to midrange area...NOW lets just hold are key boards.....
I may not have worded this right or at all but you know were I'm going with it.
here is a good read for those of us who feel the need to read it.
wish I found it a few days ago I hate math.

https://www.motortrend.com/how-to/81...e-compression/

as for the cast parts this set up is not to far past the last set up ,would a nice shiny forged rolling assembly be better maybe so but i do not foresee a problem with the power I'm making.
ok gentlemen have at it.

A good Super Stock engine will pump 140 psi on the compression gauge and make 650 horsepower and not run well on 87 octane.

If you look in the race section there are guys running 14.5 : 1 compression on 93 octane. So 11.4 with 91 should be a slam dunk.... If it's on the Interenet or in a magazine it's gotta be true.

Kinda curious why water injection became a million dollar industry back in the 70's when high octane fuel started to disappear...... Things that make one go hmmmm!

PS..... If you really want to see how good the top two Pontiac parts sellers are.... Buy all the parts from them for a 650 HP build and then when you come up with 550 HP give them a call.... This has happened recently to two forum members here, hopefully they will chime in.

Now if your still not convinced, ask them how come 99% of the fastest competitive Pontiacs engines on the planet did not come from their shops.

Early morning brain twisters! :D

Then if you're still feeling your oats ask the magazine writers how many engines they have personally built, installed and drove down the road.

I experienced that Paul some 25 years ago.

Bought the 330cfm Eddy round port CNC ported heads and his custom spec'd hydraulic roller camshaft for a 455 build. I put it together with custom pistons, small ring package, Eagle rods, stock crank, 10.5:1 compression, 2" Hooker Super Comp headers, and then proceeded to try 3 different intakes on the dyno with 2 different spacer combos. He said it's a 600hp engine all day long.

I felt it should have been, but we were also on a conservative and what I was told a very accurate DTS dyno that was used to dial in engines this person used to get his engines ready for engine master challenges (friend of dad)

Well the best intake and spacer combo barely got above 500hp but it did make 600 ft lbs. of torque. The engine however did run the number at the track we were after clicking off mid 11's at 115-ish mph in dad's 4100 lbs. GTO.

Funny part, we later found out when those same heads were put on Tony Bischoff's flow bench, they didn't flow 330 cfm :(

Sorry but I don't see the cam card posted.

When the motor is running I would interested to see how close that cranking compression calculator is. It uses 0.050" IVC plus 15 degrees. For a hydraulic cam I would want to use IVC @ 0.006"

Stan

There are 3 different thumper camshafts. By name he just called it a thumper which is the smallest but the part number he listed is the big one. So not sure which one he is referring to.

They have a Thumper, a Mutha Thumper, and a Big Mutha Thumper.

I believe the part number listed in post #1 is the Big Mutha Thumper.