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Any Recommendations?

Pump is a fresh JC split bowl pump, tight clearances, with a Berk A impeller

Don't have too much of motor specs right now. The motor is a 454 .030" over, Tunnel Ram, and dual 450dp's on top. Should be around 10:1 compression.

The heads are professionally ported 427 Rectangle, closed chamber heads, ported by Geoff Mummert. Not sure on the valves yet, won't get them until tuesday next week... but I'm sure they are on the larger side :D

I would like to turn this A impeller 5600Rpm, or at least according to the extended impeller chart. I was looking forward to Flowing the heads again and having a solid roller cut..... don't have the funds right now but definetly going to be doing it in the future.

Instead I would like to run a solid cam for right now. I'm not sure on the Piston to valve clearance and how big I can go, haven't quite measure it yet.... but I would like something around .600 for safety.

I guess that's as vague as I can get lol. I got an idea of the lift I want to run, just not quite sure on the duration, seperation, centerline, etc...

Advice?
 

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Any Recommendations?

Pump is a fresh JC split bowl pump, tight clearances, with a Berk A impeller

Don't have too much of motor specs right now. The motor is a 454 .030" over, Tunnel Ram, and dual 450dp's on top. Should be around 10:1 compression.

The heads are professionally ported 427 Rectangle, closed chamber heads, ported by Geoff Mummert. Not sure on the valves yet, won't get them until tuesday next week... but I'm sure they are on the larger side :D

I would like to turn this A impeller 5600Rpm, or at least according to the extended impeller chart. I was looking forward to Flowing the heads again and having a solid roller cut..... don't have the funds right now but definetly going to be doing it in the future.

Instead I would like to run a solid cam for right now. I'm not sure on the Piston to valve clearance and how big I can go, haven't quite measure it yet.... but I would like something around .600 for safety.

I guess that's as vague as I can get lol. I got an idea of the lift I want to run, just not quite sure on the duration, seperation, centerline, etc...

Advice?
Comp cams 280s magnum
 

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Schneider Cams makes 4 jet boat specific cams and they can custom grind cams without any problems. They're in San Diego.

The Comp Cams 280 is also a great cam, everything else right should put it around 500 HP.
 

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Tony, I'd be more apt to use a cam with a 108 lobe sep. It will help the upper mid range it will idle a bit rougher but I'd take that to get the extra pop.

It would be great if you could split the difference beween the 280S and 294B
the 280 is 242/250 @ .050 with .575/.604 lift with a lobe sep of 110 and the 294 has 256/266 @ .050 .580/.605 lift with a 108 lobe sep.

Take the lift and lobe sep of the 294B and cut the dur to 248 int. and 258-260 on the ex. I think it would do well to 6,400 but it will pull very hard above 5,000.

Just my 02.

Ask Geoff when you talk to him about the heads.

Sleeper CP :D
 

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Any Recommendations?

Pump is a fresh JC split bowl pump, tight clearances, with a Berk A impeller

Don't have too much of motor specs right now. The motor is a 454 .030" over, Tunnel Ram, and dual 450dp's on top. Should be around 10:1 compression.

The heads are professionally ported 427 Rectangle, closed chamber heads, ported by Geoff Mummert. Not sure on the valves yet, won't get them until tuesday next week... but I'm sure they are on the larger side :D

I would like to turn this A impeller 5600Rpm, or at least according to the extended impeller chart. I was looking forward to Flowing the heads again and having a solid roller cut..... don't have the funds right now but definetly going to be doing it in the future.

Instead I would like to run a solid cam for right now. I'm not sure on the Piston to valve clearance and how big I can go, haven't quite measure it yet.... but I would like something around .600 for safety.

I guess that's as vague as I can get lol. I got an idea of the lift I want to run, just not quite sure on the duration, seperation, centerline, etc...

Advice?
Advice is free. #1 don't over cam the boat. If you want to idle and not kill plugs all day then kick it down a notch.solid lifter cams are great,they create more bottom end than a hyd deal. If you want loappity loap go ahead and run a short lobe center but plan on alot of tune time and dont think about an idle below 1k. IMO 525 to 530 on the intake and 550 on the exhaust for lift. Duration @ .050 I would go 218 to 235 intake and 225 to 235 exhaust with a 110 lobe center. BIGGER BETTER idea call Chet Herbert in china Ca and ask him. If Chet is not available ask for Donny Johannson. These guys have been building motors and grinding cams longer than most of us have been driving.Again IMO. They are all I will use on cams and for thirty years have never let me down. Valve springs are the next hill to climb, You want 5600 rpm then a seat pressure of 150 lbs and open valve at 280 to 320 lbs. M
 

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my 10:1 has an Isky Z-45 and that is a flat tappet solid. I ran this combo in the pink hornet in nostalgia jet. Now, that same motor is in my 20' spectra v-drive cruiser. Love it. Get rid of the dual carbs and t-ram. Single 850 with an edelbrock performer air gap.
 

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that's alot of cylinder head IMO. Not enough CR or cubic inch for the rpm intended. I would like to see you use an oval port head such as a 781 0r 049, but then that drops your cr with the piston combo you're using. Hmm. If you could find a set of CC ovals, that would be your best bet.
 

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steelcomp was here
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that's alot of cylinder head IMO. Not enough CR or cubic inch for the rpm intended. I would like to see you use an oval port head such as a 781 0r 049, but then that drops your cr with the piston combo you're using. Hmm. If you could find a set of CC ovals, that would be your best bet.
That's the most reasonable response yet. Heads are too big, and there isn't an off the shelf cam that's going to optimize your combination. You might get close, but guaranteed you'll leave usable power on the table.

Check your PM's.
 

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People still use closed chamber heads ?

Old guy - one big reason the solid lifter gives better bottom end because if you compare it to a hydraulic with same at .050" specs (on paper) the hydraulic will be about 8° longer at .050" than the solid. Solid has lash ! That doesn't get accounted for with seat and at .050" figures since these are measured at the lobe.
 

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That's the most reasonable response yet. Heads are too big, and there isn't an off the shelf cam that's going to optimize your combination. You might get close, but guaranteed you'll leave usable power on the table.

Check your PM's.
I'll be the first to admit I don't know "jack" about BBC heads. If the heads are to large to begin with is he better off building ( cam) to the heads and trimming the impeller to rev to it (or closer anyway) or putting a smaller cam in it and never reaching their potential ?

If he goes small would something like the Comp 282S 236/236 @ .050 .561/.561 lift and 110 lobe sep or a Crane F-304-2 238/248 @ .050 .544/.567 lift and a 114 lobe sep. work better than the cam I listed before ? :)bulb

I think I'd build to the heads and the T/R intake and then worry about the impeller.

Sleeper CP :D
 

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steelcomp was here
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I don't even begin to guess at odd ball combinations like this (no offense to the OP). This is where I refer to the expert, and why I say you're not going to find anything close off the shelf.
 

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I don't even begin to guess at odd ball combinations like this (no offense to the OP). This is where I refer to the expert, and why I say you're not going to find anything close off the shelf.
Smart move. do not over cam a boat for the realistic rpm it will turn. Dream land in a jet starts at 6000 rpm and why go beyond reality. Make the boat work for what you want. IMO. M
 

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steelcomp was here
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Smart move. do not over cam a boat for the realistic rpm it will turn. Dream land in a jet starts at 6000 rpm and why go beyond reality. Make the boat work for what you want. IMO. M
Thing is, it's going to take a healthy cam to make the power needed forr this thing to pull an A. We're talking right about 550hp @ 5600, at the shaft, at the lake. That's a corrected hp of as much as 625-630. For a 454 with 10:1 c/r, that's asking a lot at that rpm, but not impossible. I had a similar engine, but with 12.4:1 and ported (by me) open chamber 990 heads that pulled a stock B to 6200 early in the AM (real good air), and it pulled one of MPD's detailed B's to 5500 in the middle of Sept. (probably 3500' DA) It had an outdated Weiand TR w/ a pair of 850 dp's and a solid flat that was 264/.600 even. I can imagine how it might have run with the right cam.
Flow numbers on my 990's were 352/252, mildly ported. I sold them to a guy with a 509, (4.35 bore. 4.25 str.) and we did a cam for him, but he has yet to run the engine. That cam wouldn't be the same for the 454.
 
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