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New Guy- POTTER from Cadillac Performance Parts.

Cadillac Performance Pts.

Well-known member
Hi Guys, I'm Potter from Cadillac Performance Parts in Tennessee. We basically engineer performance parts for Cadillac 472 & 500s. We started a crate motor program (we also have a complete line of performance parts too)and ended up doing a few engines for some of you gear reduction gearheads. These folks told me about this site and the growing interest of higher rpm 500s on the airboats. If there is anyone needing questions answered on the dudes, feel free to ask. Doesn't matter to me how you build your engine or who you get parts from, we just like to see these engines live up to their potential.It breaks my heart to see anyones project go up in smoke due to an oversite or lack of understanding of what the limit is on stock parts. Advice is free, parts are a little extra! Thanks BTW, I had absolutely no idea that a 20' airboat would run over 100MPH, ain't sure what that is in knots.
Hey Potter, nice to see you on this side of the web. Lots of great people here to. If you ever make it down this way look me up.

we all sing praises of you and your dad on here richard even though it is hard to get in touch with you sometimes.i will plug your boogie man heads and intake's richard has designend alluminum heads for the cadillac that are sure to set some new pump gas h.p/ torque numbers when they go into production i have been stashing money from my wife for when they hit the market.
Welcome Potter, I know your advice is excellent on the other forums ,so I look forward to your solid input. Can you please elaborate on the new heads? When porting Cad cast heads the intakes are frustrating. I feel the indirect runner shape and small bowl area limit me. Sometimes I think the flowbench is giggling at me half way thru the port job!! Aluminum is more fun to port anyways, and cleaner. I also wish the intake valve was moved more to the center for unshrouding, and bigger valves. Please tell me in what direction you are going with these heads. Thank You and Welcome :)

Welcome to S.A. :cheers: The cads are an awesome motor for the boats, good to see the support.

Born and raised in choo-choo town I was. Ever see any airboats up there?

Welcome Potter :D .

All of us that run something other than a Caddy are still all motor heads, so it's going to be fun to have your input on here. Nice to have ya'.

I just read in one of my Airboat World Issues that some recomend using a Holly 500 CFM 2 Barrel carb for direct drive airboats. Will that work better than my 600 CFM Edelbrock 4 barrel? Also for us direct drive guys what can we do to improve the performance of the big Caddy and push even harder? Will an Aluminum intake improve low end performance? I have read on some caddy forums that the cast intake actually produces more power. On my boat I will stay direct drive for the life of this boat and would like to start improving it a little at a time to make it really perform. This isn't just for the Caddy builder it is also for the guys who have run or do run direct drive 500 or 472 caddy's. Real life experiences would be GREATLY appreciated. I have a fully stock 500 on my boat now that I have airboat headers and the Edelbrock carb on.


Thanks for the warm welcome guys. Our heads, hmm.... Alright, we will pour the first sample in about two weeks or less. It has a raised intake port (about 1"), but also has extended intake deck surfaces to make existing cadillac intakes fit. The intake valve in moved inboard .120" and the exhaust out about .060". It'll flow (it did in testing) about 385 cfm at .700 , exhaust about 270ish. It has an extreemly small port on the intake and takes advantage of extreem air speed which will make gobs of low end power. The port is actually a little smaller than an oval port BBC. The short turn into the bowls is about the size of a fruit jar. OK, on the alum intake. You CAN make more power with better runners BUT you end up giving about 300 usable rpms on the bottom with the 2115 Edelbrock. IMO your best bet would be a 425 intake off a 77 or later. This would give more low end and would more than likely, hold it's head up to 3500 rpm or so, which is about all a wood prop can handle as far as I know. Dan, iron heads can be made to flow 320 cfm at .650 or so. To make the job easier, the floor of the intake runner on the heads can be filled from about a half inch at the opening and back to zero at the dip where it turns into the bowls. I use a special kind of epoxy and don't reccomend it for someone that has ever used it or it may end up coming loose and hanging a valve open. We have made almost 800 hp N/A with iron heads and made power to 6600 or more. Keep in mind, that that's with good parts throughout. Ain't no Edelbrock gonna do that. They are only good from 5000 or less. Usually less. Hope that helps. I will tell you this off the top of my head. Stock rods and stock valvetrain are junk. You can put ARP bolts in stock rods and possibly squeeze 5000 rpm out of em for awhile. I won't use them in a numbers matching resto project. I use the Scat ones we sell. Cheap, stout and available. As far as rockers, we make a full shaft roller set up that is bolt on except for moving the pushrod holes in toward the valve about .050". Going from 1.65 to 1.7 makes this need. Bigger cams require the shortening on the guide tops or the retainers will hit from more lift. Using a 500 cfm carb may make a direct drive boat "snappier" BUT BUT BUT, in most cases, your biggest problem with ANY carb is not enough fuel circutry to handle the needs of a Cadillac engine. The stock edelbrocks won't do it, the competition 1413 will with re-jetting and any Holley that needs more than 92 or 93 jets requires aftermarket metering blocks because they are maxed out. Even a 4500 Dom. You can takes the jets out and throw them away and it doesn't change a thing. We used to add the biggest power valves on both ends just to get the temps on the exhaust to a safe level and that's why. A stock Qjet is one of the best all around carb for boats and street use to 500 hp, BUT they need more fuel too. The carb shop on the left coast knows exactly what to do to them and for about $250, they will. We have been using the 1413 Edelbrock, simply because we don't have time to build the 800 cfm q-jets. Potter
Welcome aboard guy.

Potter what do you think about cooling the heads as questioned on here and on CB7. Is it a good idea for us airboaters weather or not if it is a Caddy? Should I have the machine shop tap the back of my heads for a 1/4" plumbing? What advantage will this have?

Typically, the biggest reason we do this on Cadillacs is due to know rear crossover in the block. The rear cyls. run hotter , especially on the drivers side, since the pass side has a heater control valve in a car and SOME water always runs through it. Cadillac even made the left rear comb chamber bigger (which is right front too) to lower compression which helps eliminate ping(detonation) on all their castings. We run lines from the top of the heads in the rear to a T and back to the front of the block, just under the T stat housing. This allows some extra cooling on the rear cylinders. You can benifit even if there is a cross over on any engine due to the way that coolant is ususally forced through the block then through the heads, but not at an even pace. The front gets naturally more flow. In real life, an engine wants the cooler water in the heads first, then into the block where higher temps make everything work better. This is where reverse flow cooling has it's advantage. The are pics on the CB7 album of that and our cooling line kits. Click on album when you first go in or substitute album for forum, the POTTER album, then New Album once you are in. The biggest overheating problem on any thing is a substandard cooling system, either by a fan with no shroud or an electric with no shroud. Even the ones with a built in shroud need 100% of the radiator enclosed.
Welcome Potter. Any advice on extra capacity oil pans for the built up Caddys. I have been told if you push the 500's hard while running dry for any distance that the capacity of the stock pan may not be enough.
I'd like some more info on using the cast intake from a 425 on a 500. I'll probably stick with the 600 cfm 4 barrel if the 500 cfm doesn't make a huge difference. Glad I didn't build my 750 for it. But if I can gain low end by putting the 425 intake on it I might get that done. What modifications are needed to do this?
On the intakes, it's kinda like using 2V intake on clevland heads or an oval port on square port heads. Smaller runners, more velocity down low, but it peters out at a lower rpm. It should just bolt on. On oil, more is always better, as it keeps temps down and greatly reduces the chance of sucking air on acceleration or de acceleration. It's incredibly hard on mains and may not even come to your attention when it happens a tiny bit at a time. Damage will stack time after time though. We also do a full sump 12 qt. pan for boats with no crossmember interferance with door and baffles. It's the same one we did for our first 700 + HP drag engine that had 2500 runs on it and has been in a street car for the last 5 years of it's life. It has had the Beegeezers ran out of it and I credit alot of the life span to oil capacity. It's never had the heads off and only the pan once to inspect when we sold the engine to the streetcar guy. It's basically only had about 3 or 4 valve adjustments and oilchanges. I have turned it over 8000 many times.
Cadillac Performance Pts. said:
A stock Qjet is one of the best all around carb for boats and street use to 500 hp, BUT they need more fuel too. The carb shop on the left coast knows exactly what to do to them and for about $250, they will. We have been using the 1413 Edelbrock, simply because we don't have time to build the 800 cfm q-jets. Potter


I'm not sure if you're still on this website, but I came across this post while doing some research. Do you happen to have the contact information for the carb shop you're referencing? I would like to get a carb for my rebuilt 472 Cadillac.