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-   -   Bbc 454 build. (https://www.offshoreonly.com/forums/do-yourself-boating-budget/358269-bbc-454-build.html)

Zone 5 04-07-2019 08:45 PM


Originally Posted by JaniH (Post 4679451)
Got my stainles marine exhaust. Em i right that these are 3" taller version risers, looks longer also. Just wondering how much overlap these can take.

You only need 112 or higher to make 500 HP, and these will be fine. Just make sure they drop to the transom, and don't flatten out. Yes, they are higher ones than "stock". without a ruler, they "look" like 3 inches in the picture

MILD THUNDER 04-07-2019 09:07 PM


Originally Posted by Zone 5 (Post 4680800)
For 500 HP you do not need some one off cam. And the cam he is suggesting is going to totally mess up the airflow in the intake. There is a reason he is on all the car sites and not this one. Don't you think that if that worked, that Comp, etc etc would be doing it?

I hate to make it simpler than it is, but as Phragle said, making 500 HP from a 454 is really basic engine building. GM was doing it in the 1960's

Comp cams and others actually have been doing that. Its not just for power, it helps the unbalanced air/fuel distribution that carbureted big blocks are known for. Just like firing order swaps can help even out cylinder to cylinder distribution. Not "mess up airflow in the intake" as you say.

I know your hatred for straub runs so deep, it brings you out of the shadows to comment , but can you at least slander him with some factual information that may be of help to the original poster ? Thanks.

MILD THUNDER 04-07-2019 09:11 PM


Originally Posted by Zone 5 (Post 4680802)
You only need 112 or higher to make 500 HP, and these will be fine. Just make sure they drop to the transom, and don't flatten out. Yes, they are higher ones than "stock". without a ruler, they "look" like 3 inches in the picture

Overlap isnt defined by "112" . its a result of timing events. In other words, duration, intake centerline, exhaust centerline, determine what the overlap will be, and when it will be. A 112LSA cam with 5* of advance built in, wont have the same overlap effect as a 112LSA cam with 2* of advance built in.

Zone 5 04-07-2019 09:19 PM


Originally Posted by MILD THUNDER (Post 4680807)
Comp cams and others actually have been doing that. Its not just for power, it helps the unbalanced air/fuel distribution that carbureted big blocks are known for. Just like firing order swaps can help even out cylinder to cylinder distribution. Not "mess up airflow in the intake" as you say.

I know your hatred for straub runs so deep, it brings you out of the shadows to comment , but can you at least slander him with some factual information that may be of help to the original poster ? Thanks.

I'm aware of what cylinder swaps do. They smooth the airflow. and they are not something that should even be discussed on a 500 HP 454 build thread, just like a one off cam Both are useless in this discussion. Your comments are not helpful in this thread, as you are implying that some exotic thing will be productive in a "ON A BUDGET" thread. I could care less what straub is or isn't doing. But for the OP to listen to him on this nonsense cam is NOT going to save him money or make it a budget build. There are multiple catalog cams that will get him where he wants to be..

Zone 5 04-07-2019 10:24 PM


Originally Posted by MILD THUNDER (Post 4680809)
Overlap isnt defined by "112" . its a result of timing events. In other words, duration, intake centerline, exhaust centerline, determine what the overlap will be, and when it will be. A 112LSA cam with 5* of advance built in, wont have the same overlap effect as a 112LSA cam with 2* of advance built in.

really? I didn't know that. OMG, I'm not giving detailed info, I'm giving a general answer on his exhaust question on reversion. There was and is no reason to get into a tech discussion on what a cam is ground at or set at or anything else. I'm trying to help the guy with basic answers to basic questions.

JaniH 04-08-2019 05:08 AM

Nice to have new blood to the discussion. What is the safe zone for gm nodular cast crank?

sutphen 30 04-08-2019 06:38 AM


Originally Posted by JaniH (Post 4680834)
Nice to have new blood to the discussion. What is the safe zone for gm nodular cast crank?

550hp and ~5800rpm

JaniH 04-08-2019 09:01 AM

550hp/5800rpm, thats enough for sure. Going to balance rods to +/- 1g both ends, pistons +/-1g. My pistons and rods aint the lightest ones. Pistons are forged speed pro l2349f. Rods are eagles I-beam with 7/16 bolts. Pistons will loose some weight because i have to shave some material from the domes, to get the compression ratio to 9.5 to 1. What is the max compression with iron heads, offcourse it depens on about the camshaft but approx? Without shaving the pistons i am at 10 to 1

Zone 5 04-08-2019 04:58 PM


Originally Posted by JaniH (Post 4680863)
550hp/5800rpm, thats enough for sure. Going to balance rods to +/- 1g both ends, pistons +/-1g. My pistons and rods aint the lightest ones. Pistons are forged speed pro l2349f. Rods are eagles I-beam with 7/16 bolts. Pistons will loose some weight because i have to shave some material from the domes, to get the compression ratio to 9.5 to 1. What is the max compression with iron heads, offcourse it depens on about the camshaft but approx? Without shaving the pistons i am at 10 to 1

Depends on the gas you have available. I ran 9.5 with 93 (and 91) octane with zero issues. Beyond that I would go on the side of caution. more CR will get you "easy" HP, within reason, but it won't help if you detonate and break stuff.

JaniH 04-09-2019 12:00 AM


Originally Posted by Zone 5 (Post 4680969)
Depends on the gas you have available. I ran 9.5 with 93 (and 91) octane with zero issues. Beyond that I would go on the side of caution. more CR will get you "easy" HP, within reason, but it won't help if you detonate and break stuff.

We have RON 95 E10 (10% ethanol) and RON 98 E5 (5% ethanol). Usually all marinas have Ron 98 E5


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