502/502 questions

[jbone]

I am running 502/502 and I put the Airgap mainifold on with a 850 demon and stock water jacketed Indmar exhaust.
The Airgap ports were significantly smaller than the ports on the alum heads. The GM Performance heads use a rounded off square intake port and the manifold is a true oval. Would I notice much difference if I port match the manifold to the heads. Keep in mind, the head opening is bigger, so there is really no material interfering with the flow. By the way, GM Performance has a dual plane manifold that is cnc finished to match the ports on the GM alum heads. Maybe that would be better.
Secondly, Would I benefit greatly from going to the lightning type JACKETED exhaust? And, is there a problem with reversion with the 502/502 cam and the lighnings?
Based on my 5000-5100 rpm at wot, it looks like I'm losing a lot of the 502 hp this engine is capable of.
Anyone know what JPC says about a Dominator pump with an A impellor at 5100 rpm.
I'm curious what hp others actually saw from the 502/502 in a jet.
Thanks,
J

[502 JET]

JPC says that a Dominator A impeller at 5100 rpm=495hp.It sounds like you have it running good now.

[jbone]

Wow!
I have a buddy with similar boat. He has the same impellor turning about 4900 rpm. His 502 is the 415 version. He has only upgraded the carb, spacer, manifold, and ignition. All the same upgrades I did to my 502/502 version.
What does JPC say about his 4900 on the Dom A impellor?
Thanks,
J

[502 JET]

JPC shows 445hp to turn Dominator A at 4900.

[WannabeRacing]

You have to get the air flow as smooth as you can.
Port matching is an absolute manditory.
It really does not matter that much that the head is larger or smaller. You think that it would because the air hits a solid ledge and would cause problems. But the other way around can create almost equally poor results. The velocity will immediately change, leaving the fuel to drop out of suspension. Also, the pockets where the head runner increases will swirl, vortex, create voids, and lose velocity as well as fuel suspension. Make that transition smooth. Just lay the gaskets out to the head, then match it up to the intake and make the marks. Then just slowly increase to that size. It would be optimum to have a professional do it, but we are all hacks around here. Just make sure you slowly increase the size, not all right at the edge. It will make a greater difference the more rpms you are running. But will still make a big difference throughout the engines rpm band.

[jbone]

Thanks guys,
Next time I have the intake off, I definately have it done.
As far as the exhaust, I'm still curious as to how much I might actually gain with a Lightning type exhaust.
J

[jbone]

Now that everyone is back from the big weekend, any idea what gains I might see by going from the Indmar exhaust to the Lightning water jacketed headers.
I'd like to get an idea before shelling 2K.
Thanks,
J

[Dan Lorenze]

Wow!
I have a buddy with similar boat. He has the same impellor turning about 4900 rpm. His 502 is the 415 version. He has only upgraded the carb, spacer, manifold, and ignition. All the same upgrades I did to my 502/502 version.
What does JPC say about his 4900 on the Dom A impellor?
Thanks,
J
Hey J, I also have the 502 415 version like your buddy has, mine's a Marine power with a Demon. My Ultra has a setback Dominator turning an "A" right around 4800 rpm. Honestly, I thought the thing would turn better numbers. I've been told that Lightnings might be the way to go for my next mod, I hear they're lighter and flow better than the stockers... I haven't seen 60 in the boat yet but that's what I'd like to see. :) I'm somewhere right below 60.
Dan

[jbone]

Hey J, I also have the 502 415 version like your buddy has, mine's a Marine power with a Demon. My Ultra has a setback Dominator turning an "A" right around 4800 rpm. Honestly, I thought the thing would turn better numbers. I've been told that Lightnings might be the way to go for my next mod, I hear they're lighter and flow better than the stockers... I haven't seen 60 in the boat yet but that's what I'd like to see. I'm somewhere right below 60.
Dan
I think my friend got lucky with his setup. He has your motor in a 22 Shockwave. It is similar to the 22 Stealth. This off season he added the 750 demon double pumper, 2 inch carb spacer, Airgap intake, and the MSD drop in distributor. He went from a 60-61 mph boat to 64-65 mph boat. He is stoked.
I think next year I do the lightnings. If you get them first, let me know how well they worked for you.
J

[Dan Lorenze]

Good info, thanks..... :)

[cstraub]

Jason,
Curious on how the 502 Crate engine compares to your old set up with the heads and cam? What did you do with the old engine?

[Bad Ass Randall]

I ran a zz502 crate motor with lightning headers no problem with reversion. Also have the cnc intake and heads if anyone interested.

[victorfb]

I ran a zz502 crate motor with lightning headers no problem with reversion. Also have the cnc intake and heads if anyone interested.
are you talking the GM aluminum heads and intake? and how much are you asking?

[jbone]

Sent a pm

[22HotKat]

I have a ZZ502 infront of a Legend Pump with an "A" impeller + inducer
Lightning headers 850 Demon - MSD. I changed the pan to a 10QT - very mild port work , stock ZZ 502 cam until this winter. I have been running this since 2000, 5200 RPM until the temp gets over 95. I have the port matched dual plane ZZ intake. No reversion issues. I just swapped the cam for a custom Ultra Dyne that I had cut 3 years ago and never installed.
A little more duration and .600 lift - 112 LSA
I'm now at 5300 RPM hoping some tuning will get it to 5400
I had a bung put on the pan for a temp sensor for my oil temp gage
Get an oil cooler on that motor if you don't have one

[jbone]

I have a ZZ502 infront of a Legend Pump with an "A" impeller + inducer
Lightning headers 850 Demon - MSD. I changed the pan to a 10QT - very mild port work , stock ZZ 502 cam until this winter. I have been running this since 2000, 5200 RPM until the temp gets over 95. I have the port matched dual plane ZZ intake. No reversion issues. I just swapped the cam for a custom Ultra Dyne that I had cut 3 years ago and never installed.
A little more duration and .600 lift - 112 LSA
I'm now at 5300 RPM hoping some tuning will get it to 5400
I had a bung put on the pan for a temp sensor for my oil temp gage
Get an oil cooler on that motor if you don't have one
Thanks for responding. It is nice to see how my ZZ compares to others in similar applications.
Did you have the heads flow tested after the port work? If so what numbers did you see?
Do you have all the cam specs for the cam you used and what jets are you running in that demon?
Lastly, why do you say to put an oil cooler?
J

[22HotKat]

The cam specs are Duration @ .50 Intake 232 Exhaust 240
Lift .601 both intake and Exhaust
The cam that comes with the 502-502 is a Crane Steel Billet
Probably designed for a 70 Chevelle - killer torque from 2000 - 4000 then drops off. If you go over .600 lift you will need longer lifters as they will fall below the lifter guides - see the Crane web site or call them
Heads
Per Tom Sallee - Sallee Cheverolet the 502 -502 heads are Edelbrock Performers. These are really well suited for a 500 inch motor with a top RPM in the 4800 - 5800 range. They call them "RECTOVALS" as the ports are bigger than an oval port Chevy but smaller than Rectanglur. That's why your oval port intake didn't line up. The advise about using the intake gasket for a template and grinding the intake to match the heads is good. If you want to spend some $$ call Edelbrock and I bet they have that item already done and waiting to be bolted on. No the heads on my boat haven't been flow tested - the porting wasn't to remove material just clean up casting marks and smooth the rough areas
Oil Cooler
A boat engine is under constant load v/s a car that runs at 1/2 the RPM and gets to go down hill and coast. If you take a look at just about any Mercury out drive boat you will find an oil cooler. I have an oil cooler and a Oil Temp gage. The oil runs between 190 deg and 225 never over that. For mineral based oil they say to keep it under 220 deg , it starts to break down at 240 deg and starts failing at 270 deg. Full synthetic has a higher tolerance. I looked in the CP catalog and Hardin catalog today to see how many degrees a cooler lowers the temp. Lots of coolers for sale no facts about temp drop.
If we have the same motor and its generating the same heat I would assume the cooler has to be dropping the temp by 30 - 45 deg. So do the math and you could be as high as 255 - 275. A simple way to tell is go on a hard run and stop and idle - look at your oil pressure gage. If your pressure is between 5 and 10 PSI you may want to invest in a cooler. It's cheap to change you oil over to full synthetic so some added protection.
Installing a cooler - 2 main options. Your block has 2 plugs by the oil filter for oil cooler lines. You have to be aware of 2 check valves under the oil filter that need to be changed. The other option is to put an adapter where the oil filter is and use a remote filter and oil cooler. Kens - CP both sell billet adapters - don't use a $10 adapter from Kragen. You don't want to risk your investment on a POS part.
If you think you have restrictive exhaust changing the cam or working on the heads won't improve your performance
Good luck

[jbone]

The cam specs are Duration @ .50 Intake 232 Exhaust 240
Lift .601 both intake and Exhaust
The cam that comes with the 502-502 is a Crane Steel Billet
Probably designed for a 70 Chevelle - killer torque from 2000 - 4000 then drops off. If you go over .600 lift you will need longer lifters as they will fall below the lifter guides - see the Crane web site or call them
Heads
Per Tom Sallee - Sallee Cheverolet the 502 -502 heads are Edelbrock Performers. These are really well suited for a 500 inch motor with a top RPM in the 4800 - 5800 range. They call them "RECTOVALS" as the ports are bigger than an oval port Chevy but smaller than Rectanglur. That's why your oval port intake didn't line up. The advise about using the intake gasket for a template and grinding the intake to match the heads is good. If you want to spend some $$ call Edelbrock and I bet they have that item already done and waiting to be bolted on. No the heads on my boat haven't been flow tested - the porting wasn't to remove material just clean up casting marks and smooth the rough areas
Oil Cooler
A boat engine is under constant load v/s a car that runs at 1/2 the RPM and gets to go down hill and coast. If you take a look at just about any Mercury out drive boat you will find an oil cooler. I have an oil cooler and a Oil Temp gage. The oil runs between 190 deg and 225 never over that. For mineral based oil they say to keep it under 220 deg , it starts to break down at 240 deg and starts failing at 270 deg. Full synthetic has a higher tolerance. I looked in the CP catalog and Hardin catalog today to see how many degrees a cooler lowers the temp. Lots of coolers for sale no facts about temp drop.
If we have the same motor and its generating the same heat I would assume the cooler has to be dropping the temp by 30 - 45 deg. So do the math and you could be as high as 255 - 275. A simple way to tell is go on a hard run and stop and idle - look at your oil pressure gage. If your pressure is between 5 and 10 PSI you may want to invest in a cooler. It's cheap to change you oil over to full synthetic so some added protection.
Installing a cooler - 2 main options. Your block has 2 plugs by the oil filter for oil cooler lines. You have to be aware of 2 check valves under the oil filter that need to be changed. The other option is to put an adapter where the oil filter is and use a remote filter and oil cooler. Kens - CP both sell billet adapters - don't use a $10 adapter from Kragen. You don't want to risk your investment on a POS part.
If you think you have restrictive exhaust changing the cam or working on the heads won't improve your performance
Good luck
Thanks for taking the time to respond in detail. I am running a remote filter and did change out the 1 check valve to I believe a 30lb. The other, for the remote cooler was left the same.
I may try to find an easy location to place a temp sensor and guage to see temps after hard runs.
Thanks again,
J
J