Performance Boats Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
436 Posts
Discussion Starter #1
Other than weight savings and the ability to inhibit detonation, do today's aluminum heads really flow substantially more than a good set of 990 heads?
 

·
Registered
Joined
·
436 Posts
Discussion Starter #4 (Edited)
I think the cam is curently the bottleneck on my setup.

Old school Offenhauser tunnel ram with dual 750dp Holley's (6109's)

990 Heads

Cam is the old Erson JB100 - 315 lift at the cam (542 at the valve) on both sides

Duration is 235 @.050 on both sides

Lobe centers are at 112 (I think!)

I would like to change to a roller set up, open her up a bit, and still run wet headers!

Good cam combo to do that with 990 heads out there?

Old combo revved to 5700-5800 with fresh MPD pump (Stainless AT "B" with inducer)

Would like to improve from there.....
 

·
Swollen Member
Joined
·
216 Posts
Look at these flow numbers for Dart Pro 1's and you tell me if there is a big difference..................um.......that would be a yes.
 

·
Banned
Joined
·
1,263 Posts
Newer heads not only flow more, but have better port and bowl shapes, cross sectional areas, , combustion chamber design, and some are developed with wet flow. Note: Merlin's are kind of excluded from this list, although a little better than stock.

Most, not all, have raised exhaust ports and some raised intake ports.

Alot has been learned since the 60's/70's.
 

·
Banned
Joined
·
3,605 Posts
Newer heads not only flow more, but have better port and bowl shapes, cross sectional areas, , combustion chamber design, and some are developed with wet flow. Note: Merlin's are kind of excluded from this list, although a little better than stock.

Most, not all, have raised exhaust ports and some raised intake ports.

Alot has been learned since the 60's/70's.
Merlin's, is that because they are an older design or?

Thought's on ProComp heads?
 

·
B.A.M aka "Black Azz Mike
Joined
·
2,925 Posts
Hey Jeff! Finally pulling the mill to refreshen her up:)

I would def step up in cam. You can achieve more with a better cam. Contact chris Straub on here and he can set you very straight with a nasty cam kit that will scare you!!!!! Talk with him about your top end kit;) I promise that you will be very happy:)
 

·
Registered
Joined
·
436 Posts
Discussion Starter #11
Hey Jeff! Finally pulling the mill to refreshen her up:)

I would def step up in cam. You can achieve more with a better cam. Contact chris Straub on here and he can set you very straight with a nasty cam kit that will scare you!!!!! Talk with him about your top end kit;) I promise that you will be very happy:)
Yeah, She kinda forced me into it with the oil pump taking a dump on me.

It's been a nice strong and reliable motor for years. Time to step up though....

Thanks for the info!

Jeff
 

·
Registered
Joined
·
8,169 Posts
Heart of the motor

Yeah, She kinda forced me into it with the oil pump taking a dump on me.

It's been a nice strong and reliable motor for years. Time to step up though....

Thanks for the info!

Jeff
Any question about which "out of the box" oil pump to use?.............MP
 

·
E-7 Sheepdog (ret)
Joined
·
6,834 Posts
Just keep in mind engine size and intended RPM.

More flow is not always better. Beyond a point, it will hurt you.

Here is a VERY hard running set of factory irons:

2.19" intakes, 1.80" exhausts, on 11/32" stems
Lift ---- Int----Ex
.050 -- 31.8 -- 26.1
.100 -- 67.2 -- 56.8
.200 - 146.3 - 113.0
.300 - 221.9 - 147.0
.400 - 270.7 - 176.6
.450 - 277.0 - 189.8
.500 - 283.4 - 198.6
.550 - 291.8 - 201.9
.600 - 297.0 - 203.0
.650 - 297.0 . 204.1

That's better than 990's from the box, and mine are not rectangles, never were.

Those produced a VERY hard running 454 that otherwise is "handicapped" by 8:1 compression and a hydraulic cam (and 1 too-small carb on a dual-plane Perf. RPM Air Gap intake).
It makes 500HP at 5,400RPM, Aggressor B impeller in a Berk F, no inducer (but now blows the pump dry if I stomp it from idle (never did that before)).
Spun her to 5,900 with the big nitrous jets 2 weeks ago teaching a TX driver a thing ot 2. LOL


Just don't go TOO big looking at head flow unless you have a huge motor or intend to spin huge RPM.

Something that fits will work wonders, something that does not, will require duct tape and bailing wire.
 

·
Hit it where you fit it
Joined
·
136 Posts
Any question about which "out of the box" oil pump to use?.............MP

I have been running the Milodon high volume/high pressure one for years and feel it is the best for the money. It runs about $75 in Jegs and has never let me down. 50 psi at idle and 80 wide open when hot....
 

·
I'm No Expert
Joined
·
3,139 Posts
Actually don't think it was the pump, XClutchboy725 i though i remember seeing a post from you saying the pickup or the end up the pickup came off?

I run the Melling high volume oil pump (MEL-M77HV), just remember you should take this pumps apart and check clearances. I though i remember somebody saying there was a pump that came perfect out of the box.
 

·
steelcomp was here
Joined
·
26,516 Posts
Here's the numbers I have on a set of 990's that I ran for a few years. I did the port work on them and I can say, they weren't radical by any means. Just a 2.25 intake, some bowl blending and wall straightening, and a good valve job. I only flowed the good port as the bad port is usually a certain percentage off that can be estimated, and this was for designing a cam. You can see these heads kept right on flowing at the higher lifts and never peaked out. The weak side is the exhaust, but as you can see, these flow plenty for most small ci. big blocks. Remember, what's important is the ratio of port volume to flow. You can get big numbers with big ports, but velocity will be down, which is a bad thing. The smaller the port and better the flow numbers, the better off you'll be. That's where the more modern designs will be ahead of the game. I'm not sure what the port volume ended up being on these heads, but as a comparison, my Canfield 310's flowed about the same with very little port work. (820hp on 467ci) My guess is the 990's would cc out at about 325-330cc's, or bigger. None the less, these 990's would work real well up to 500ci. and could probably support 800hp or so. The 990's were also flowed on a 4.31 bore fixture. Be careful analyzing advertized flow numbers. They're always flowed under max conditions. Big bore diameters, ex pipes and intake radii. If you're putting heads that were flowed on a 4.600 bore fixture on an engnie that has a 4.31 bore, they're not going to flow anything lke the advertized numbers. Just FYI.

990 heads:
Intake:
.100...67.7
.200...139.8
.300...213.4
.400...265.6
.500...300.4
.600...322.4
.700...341.0
.800...352.3

Ex:
.100...64.1
.200...116.5
.300...147.0
.400...174.0
.500...198.6
.600...219.9
.700...237.2
.800...252.0
 

·
steelcomp was here
Joined
·
26,516 Posts
Look at these flow numbers for Dart Pro 1's and you tell me if there is a big difference..................um.......that would be a yes.
Put those darts on a 4.31 bore fixture and see what happens to the flow numbers.:)devil
 

·
Cantard
Joined
·
5,017 Posts
Put those darts on a 4.31 bore fixture and see what happens to the flow numbers.:)devil
LOL I was going to stir the pot. Thanks for doing it for me. Just put a set on a 468 and not all that impressed. In my mind it came up 50 hp short.
 

·
Nobody
Joined
·
1,720 Posts
Just keep in mind engine size and intended RPM.

More flow is not always better. Beyond a point, it will hurt you.

Here is a VERY hard running set of factory irons:

2.19" intakes, 1.80" exhausts, on 11/32" stems
Lift ---- Int----Ex
.050 -- 31.8 -- 26.1
.100 -- 67.2 -- 56.8
.200 - 146.3 - 113.0
.300 - 221.9 - 147.0
.400 - 270.7 - 176.6
.450 - 277.0 - 189.8
.500 - 283.4 - 198.6
.550 - 291.8 - 201.9
.600 - 297.0 - 203.0
.650 - 297.0 . 204.1

That's better than 990's from the box, and mine are not rectangles, never were.

Those produced a VERY hard running 454 that otherwise is "handicapped" by 8:1 compression and a hydraulic cam (and 1 too-small carb on a dual-plane Perf. RPM Air Gap intake).
It makes 500HP at 5,400RPM, Aggressor B impeller in a Berk F, no inducer (but now blows the pump dry if I stomp it from idle (never did that before)).
Spun her to 5,900 with the big nitrous jets 2 weeks ago teaching a TX driver a thing ot 2. LOL


Just don't go TOO big looking at head flow unless you have a huge motor or intend to spin huge RPM.

Something that fits will work wonders, something that does not, will require duct tape and bailing wire.
Curious, are they 049's???..
 
1 - 20 of 27 Posts
Top