mrhorsepower1

With the 468 cu.in combo we run in the Rum Runner "A" class boat. The rules allowed 12.0:1 compression, any cam, 1 X 4 carb, wet sump, and we made 740 Horsepower @ 6500 rpm. Mechanical roller camshaft. .714/.714 lift duration @ .050 262/268 . Torque curve was very broad and strong 640 peak. and a 1050 cfm dominator carb.

mrhorsepower1

Rookie

iTrader: (4)

Sorry, can't forget RUM RUNNER. Didn't know they were running a 468.

Panther

You can lead a horse to water but.....

mrhorsepower1

Should of ran less cam....huh Frank.

Keytime

I have a situation where the engine-builder says they're over 9.5:1 and the owner thinks they're 9.5:1. I've talked to both. I'm not extremely engine-saavy, so I was drinking from a firehose when the builder was talking about specifics. He did say they had Grumpy Jenkins heads (Dart), Lunati internals, etc. He said the best parts were in it and they're very reliable. His expertise is more in cars, so I'm trying to figure out how well he should know they'll perform in a boat.

I'll have this boat checked out by Advanced Marine at LOTO. I've called there to talk to Matt, but he's been gone. I'll try to talk to him tomorrow.

What can they tell me about the engines when I bring them in? What can they verify?

mrhorsepower1

The only components they will be able to determine are going to be external on the engine- cylinder heads will have world products cast into them, or "merlin" , cylinder block, oil pans, intake manifolds, carbs....ect.. Internal parts you really will not know what you have until you open them up. If you can get a build sheet or receipts on the engine build would help. Cam card, piston part number, a detailed itemized component and labor break down would be great. There are many ways to make horsepower with a given cubic inch engine. The key is the right combination for your application. The engines may have all of the Brand name parts, but if the camshaft is incorrect or the cylinder head intake runner volume is too big, the engine will not perform very well for marine use.

jeff1000man

You can make the power, but will the engine idle? If you put enough lift and duration, a lot of things are possible, but what about the center line. Are you going to have a reversion problem.

With really good head work and the right cam you can get there, but that is a lot to expect from an NA engine.

I would rather have one with a small blower and smaller cam so that the valve train would last a little longer.

Little young in this business, What do you guys think about my opinion?

I have a little 468 that I built out of left over stuff in my shop that makes 9.5:1 that I use for experiments. I put a .560, 248 solid flat tappet cam in that I want to try out in a couple weeks when my Dyno gets here. Has ported 049 iron oval heads on it. I'll let you know what it makes, but I think it is going to be low 5's

Young Performance

I hope you wrote that down Dean

I can't believe I've been doing it wrong all these years
I should have paid better attention in school

Young Performance

I think you pretty much nailed it. Why put a GORILLA camshaft in there and spin it to the moon unless you have to. Those instances are rare, like in a limited class of racing. You can only use certain parts and do certain things, so you do what you have to in order to make the most power you can. That is a race motor that may or may not stay together. That is not what you want in the family cruiser.
I'm of the opinion to build more cubic inches and keep the rpms down by putting together a package that works and makes your target horsepower with as little camshaft as possible. If you can't make the number that way, then give it some artificial atmosphere (that's a blower for those who don't understand)