• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

BBC 502 upgrades and builder?

M

MidnightRuder

Member
I have a ZZ502 on a 18x8 alumitech hill with 2.3:1 century belt drive.

It's used for bowfishing and looking to pull motor and rebuild over the winter or find a builder.

I've read about alot of different upgrades for motor and trying to find out from 1st hand experience from others.

Any builders you would recommend or upgrades?
Thx
 
Has the factory ZZ502 met your performance needs ?

Has the engine experienced any defect or is it currently posing a concern ?

How many total time hours has your engine logged ?

This will give anyone who replies a good baseline to provide advice.
 
I would like to get more power out it
SWAMPHUNTER45 said:
Has the factory ZZ502 met your performance needs ?

Has the engine experienced any defect or is it currently posing a concern ?

How many total time hours has your engine logged ?

This will give anyone who replies a good baseline to provide advice.
Click to expand...
I would like to get the most out of it as I could but durability and reliability are the main concern.

It has 500 hours on it now and nothing is wrong as of right now. Just don't wanna keep pushing it and really destroy something.

I just wanna build it right the 1st time if at all possible
 
Where are you located ? Proformance Unlimited in Melbourne Florida builds airboat motors. They build a nice 540 with 502 block. Fuel injected all forged 700/700 plus. Damn near a drop in motor out of the crate right around 17.5-18k
 
If you want a good gain and solid reliability I would look to a BBC 540

I have never met someone who was unhappy with a purpose built 540 and years ago BlackWater made a beast mode reputation running EFI 540s with big 4 blade props paired with a 2.55 on their tour boats.

SwampThang got a custom EFI 406 sbc done by Smedding Performance in Texas. It is a little beast putting out 500+ hp and torque.
All forged internals, nitrous rated and Dart block.

I had them build me the same engine and have been very happy with their build quality.
They offer a 540 and 632 inch big block.
I think the 540 geometry is the better airboat choice.

The ZZ502 is advertised as putting out 508hp at 5,200rpm and 580tq at 3600.

The basic 540 that Smedding Performance build puts out 620hp at 5,400rpm and 680tq at 4,300rpm. They dyno every engine and will ship it with a curved distributor, properly jetted carberator right to your door.

Give them a call and see what they suggest.
210-446-0960 ask for Jacob
 
Smeding is a good company they just built a 540 just go on YouTube and look it up I would use them or Prestige Motorsports
 
Last edited:
One observation that I had made over the years on the 502 platform was that for some reason they used more oil. The ones that I had been around would consume a quart every 10 running hours. Even the lower hour engines would do this. Only things I can reason is it was due to the large bore and a shorter stroke and how the oil is distributed. Where the longer bore of the 540 or 632 has a larger surface area to disperse it. Another theory could be that most were GM units like yours and they used hyperutectic pistons and most airboats run cooler than cars as such the clearances may be looser in the bore.

Just odd because I ran 454 engines for thousands of hours with out a similar observation. The Branch Cadillacs didn’t use a drop of oil even through the break in process regardless of piston used. The only observation with the Cad platform was noise you could hear when running forged pistons until the engine warmed up.

Curious if you had noticed your 502 consumed a little oil over say 10-15 hours ?
No visible smoke just a tendency to use oil during operation.
 
Just a bit of input here, Gerald "Old glory camp"Motes has a 416 Waterthunder on a 16' Davis hull, nearly ran over his Lincoln Navigator due to throttle hanging open while dry loading, weight vs horsepower, this is no light boat by any means.
 
We just built a 540 out of a 502 block for a customer for his 66 Chevelle that I'm now putting in the car for him. With Edelbrock Vic Jr. heads, Vic Jr intake and a 950 ATM carb made 730 hp. Don't remember the tq spec or cam spec right now.

I see you're in Alabama which is a ways away from Venice FL. where we're located. Stroke kit is the best bang for the buck on a 502. We could build a turn key engine with a dyno sheet.
 
Last edited:
You must log in or register to reply here.
Back
Top