[slowbird]

Decent article although i wise they talked more about the heads and work if any work was done to them
https://www.motortrend.com/how-to/48...e1B6OEcjx2OCD4

[steve25]

Judging by the out of the box flow numbers for the two sets of KRE D port heads that I have ported, and the Hp numbers posted on the kRE web site the heads used on that 488 build would have had to have been ported to between 290 and 300 cfm by my math!

592 hp / 8 = 74 per cyl

74 / .43= 172 cfm@10” H20

172 x 1.67 = 287 cfm@28” H2O

[slowbird]

Originally Posted by steve25

Judging by the out of the box flow numbers for the two sets of KRE D port heads that I have ported, and the Hp numbers posted on the kRE web site the heads used on that 488 build would have had to have been ported to between 290 and 300 cfm by my math!

592 hp / 8 = 74 per cyl

74 / .43= 172 cfm@10” H20

172 x 1.67 = 287 cfm@28” H2O

Not sure those equations ends up with accurate info using them like you are. I just tried them on a couple combos and 1 showed over 70cfm more than reality.

[Stan Weiss]

Originally Posted by slowbird

Not sure those equations ends up with accurate info using them like you are. I just tried them on a couple combos and 1 showed over 70cfm more than reality.

Brian,
While I have used that formula for a quick and dirty calculation, as you say many times it come up off. It assume a great number of thing. As an example. If you have an engine and only change CR then HP should increase with the same head flow.

Stan

[Dragncar]

Looks like a factory 4 bolt block. Caps anyway. Not sure if I would use a factory 4 bolt for a engine that that.
Awful nice set of rods for a 600 HP engine.

[steve25]

Sorry if it’s not a dead on cfm number as I myself have seen motors with 300 cfm heads make much much closer to 700 hp due to the other quantity of factors involved, but in your post you just wanted to know “ if work had been done to them “ and with out of the box numbers of about 260 cfm then you know what the answer is!

[Formulas]

A formula like that probably assumes a certain VE. Which can vary

Deductive reasoning figuring what you dont know from what you do know
But if you dont know enough then it's a WAG

Like working a puzzle it's a WAG to start with one piece in the center deductive reasoning is when there is one open hole at the end of a puzzle and you then KNOW where the last piece goes

[FrankieT/A]

Originally Posted by Dragncar

Looks like a factory 4 bolt block. Caps anyway. Not sure if I would use a factory 4 bolt for a engine that that.
Awful nice set of rods for a 600 HP engine.

Looks like a 428 block...

[Formulajones]

I'd say the heads are a bit on the small side for that engine.

I see a vacuum pump, a big single plane intake, a 242 @ .050 camshaft, 488 inches with over 11:1 compression,,,,,, and only 592hp??? Torque isn't bad but I've seen over 600 on 455 builds so I would at least expect that with a 4.5" crank build.

[pontbil]

Nice video do you know who makes that lifter bore brace?

[Mike Davis]

Originally Posted by pontbil

Nice video do you know who makes that lifter bore brace?

KRE sells that brace.

[tom s]

Having been on that dyno and spent a day with Steve with that combo he would have predicted 1.25 HP per CI on his pump.He has engines on that thing EVERY day of the week.A master at tuning.Takes months to get a appointment.The Engine Masters program take one week a month on it.Not know to be a "happy" dyno.Tom

[Skip Fix]

I'm just thinking that small a cam to make 600 HP? Granted some CI.

What does the brace do for a mild HR cam and lifters with link bars?

[slowbird]

Originally Posted by Skip Fix

I'm just thinking that small a cam to make 600 HP? Granted some CI.

What does the brace do for a mild HR cam and lifters with link bars?

I made 620+ (mostly like 630-640 if i didn't have issues that day) with hyd roller and same duration as the 488ci but mine was 461ci

[Dragncar]

Originally Posted by FrankieT/A

Looks like a 428 block...

If thats the case its kinda a weird build. You would think with a 4.5 " crank you would wand the extra meat around the mains a 400 block would give you.
And with the small bore of the 428 block he would have been better off with a 455 block.

[Dragncar]

Originally Posted by tom s

Having been on that dyno and spent a day with Steve with that combo he would have predicted 1.25 HP per CI on his pump.He has engines on that thing EVERY day of the week.A master at tuning.Takes months to get a appointment.The Engine Masters program take one week a month on it.Not know to be a "happy" dyno.Tom

I called them up 2 weeks ago and they were just over one month out. The closest dyno to me has never had a Pontiac on their dyno. So some sort of fabrication would be need to hold up the front of the engine.
And Westech has a 1150 dyno carb I would like to try after my 1050 is used.

[Skip Fix]

Originally Posted by slowbird

I made 620+ (mostly like 630-640 if i didn't have issues that day) with hyd roller and same duration as the 488ci but mine was 461ci

Cool! What cam were you using?

[Dragncar]

Originally Posted by pontbil

Nice video do you know who makes that lifter bore brace?

KRE makes it, bought one. Its still in my toolbox.
The SD brace is much better IMO. With the KRE brace you need to drill and tap for 5/16 bolts right on top of your cam bearing bosses. So it "pulls down" with bolts.
The SD brace, no drilling or tapping of your block and the ability to support the lifter bores is far greater.
No comparison.

[Stan Weiss]

Originally Posted by Dragncar

If thats the case its kinda a weird build. You would think with a 4.5 " crank you would wand the extra meat around the mains a 400 block would give you.
And with the small bore of the 428 block he would have been better off with a 455 block.

The difference in bore size between a 428 and 455 is only 0.030"

Stan

[Formulajones]

Originally Posted by slowbird

I made 620+ (mostly like 630-640 if i didn't have issues that day) with hyd roller and same duration as the 488ci but mine was 461ci

That's what I'm talking about. For a 488 with that much compression and a bunch of "race car" stuff on it, I'm not overly impressed. It's okay, more of a torque everywhere engine with the big crank.