850/900 hp
 

I am at the design stage of building a new engine for the Daytona.
What would your build consist of. Money is an issue but do want good parts but not overkill. I will assemble the engine myself after all of the machining is done by a local shop I have used for over 20 years. I have built performance engines for 35 years.
It will be natural aspirated, roller cam, tunnel ram? F.A.S.T.
electronic fuel injection.
What cubes - 598 or 632?
Plan on using a tall deck block.
I have dry exhaust so cam overlap is not an issue.
Would you do the firing order swap?
Thanks
Steve

I would buy a used engine that the owner has already sunk double the amount of money into than it is worth. Then you can pull apart, inspect, and still be ahead of the game.

I have been looking.
Boat forums, racing junk.
Where else should I look.

Sounds like some high dollar parts,

Tink , I just reread your post and see your goal is 850 - 900 . A blown 540ci would be more like it for your horsepower goal .

I agree 100%, blown 850 or 900 can go 200-400 hours (if its not a Mercury) these days,

I would suggest if you are going NA use a big tunnel ram intake with as much volume (bath tub style) as you can! At high RPM the cylinders have a larger amount of atomized fuel to pull from, 5800 and up rpms. dual quads for sure! either Carbs or T/B. IMO

Your biggest power gains in a N/A motor will be in the headwork, make sure you have the heads done at a reputable shop as it will be the most critical part or the HP equation again JMHO.

Good luck

NO blowers - I have Pro 1 heads set up by Jim Valakeo now. May need a bigger set or have these hogged out.

Then go with a 705cu inch setup. Randy at cobra built a bunch of these years ago.

should be able to get 900 HP out of 632 pretty easy.

[QUOTE=T inke rer;402868Should be able to get 900 HP out of 632 pretty easy.[/QUOTE]

1.42hp per ci, without a supercharger, can be done, but don't think I'd call it "easy".

It's definitely not going to be a low lift, smooth idling, low rpm, low compression, long valve train life engine. Now, something like a 572-598 setup, with a good rod ratio, mild hydraulic roller cam, good cylinder heads, a 10-71, 14-71......can be very docile, have good valve train life, meet your power goal easily on low boost.

As long as your cool with running a big solid roller , big compression, tunnel ram set ups, Should make for some wicked sounding engines. How long would you like to get out of your valvetrains?

You can always try Sonny's for a top half kit. Use it with a Brodix 5" bore space block.

http://www.sonnysracingengines.com/b...-marine-engine

900 is easy with a 632. Gonna run about $16,000 for all the parts.

Don't forget to talk to your drive guy about all that torque a large motor will produce.. Spin it to the moon to help save the drive.

You should sell him your 11.625 block, would help with the rod to stroke ratio.

Now we're talking. Good for a 5 to 5.5 stroke :)

I would use a block taller than 10.2 to build the 632. That way you can put a decent length piston in it.

No problem, a 598 will work as well. You could do it with a 572 if you want to turn a bit more rpm. Talk to Bob Madara about the valve train and overall combo, he has several customers running similar power. I know Wet vette on here has been running probably closer to 1000hp NA for many years. I have helped a couple of Bob's customers convert to EFI which will really helps with the dock manners, idle, in and out of gear, etc. As long as your heads are up to the task, the rest is fairly basic. I wouldn't run any taller then 10.2, those foot long pushrods are a killer. Call Bob - Drink now ICDEDPPL :stooges:

1000 HP N/A, that's a lot.

can a pump gas 632 make 1000 hp?the op said his goal is 850-900 n/a.i think 800 would live much longer.

We all know about and we all play the "trade off game" when it comes to building our power. I believe the OP has to decide if he want's to have a big vacuum pump with a soggy bottom end (900-1000) NA motor or something more manageable (800) NA I agree with Mike about longevity, but only the OP can make that decision. I have had both versions over the last 40 years, and lately lean towards strong reliable power over brut solid lifter cam, big cfm carbs that have low engine vacuum, Not talking blowers or fuel injection, but I digress.

the op did not say but im thinking he wants a pump gas engine,something that he can fill up on the way to his favorite boating spot.that kinda limits the hp also.

Agreed!

I agree that a 900hp blower combo is much easier to build, and will be a milder engine. But, 900hp from a 598, or 632 is not unattainable, and the OP clearly stated he doesn't want blowers. So.... If it were me, I'd shoot for 10.5 to 10.75 comp, low lash solid 55mm cam, .904 lifters, 7000rpm, heads that flow close to 450cfm with the smallest chamber you can get, steel shaft rockers, Ti valves, tunnel ram with EFI, and a dry sump for sure. With the money you save on the blower, you can purchase lighter, better quality parts and components to help with longevity and durability. You'd have a hard time making that power with a conventional off the shelf ring pack, and a wet sump. I always think it's cool to do something a bit different. It'd be great if we could get some of the big power NA guys to post their experiences on this thread.

alex,do you think gas ported pistons would be good on this build?i know a lot of drag race guys use them but i dont know about longevity in a marine engine.

A pair of those would sound wicked in a Daytona screaming past the sandbar. I'd buy two tickets for that show :coolcowboy:

or one in a 26 daytona!

oops, I thought for some reason in my head Tinker had a 33 Daytona.

Yes, I'd use a lateral gas port with a lower tension .043 barrel faced top ring. It will actually reduce ring wear because it only applies additional pressure on the power stroke, the rest of the strokes the lighter ring tension will help reduce wear and free up HP.

What about a 4 5/8 arm 615ci

Thank you Haxby for sharing some of your knowledge and technical info.. feels like threads of old

A couple of years ago we worked with Bob Madara on a set of carbed 572's dry sump engines and made 804 HP at 6100 RPM. They have good idle and run on 93 octane.

You can get a 10.4 block from dart and put a little longer rod in to help with piston speed.

10.4 block?can you explain how rod length affects piston speed?

Longer rod lets the piston dwell at the top and bottom of the stroke for a longer period of time. Doesn't change the speed in between. If I was to build 632 for a marine application I would want the longest rod possible. Dart does run off some 10.4 blocks usually have to wait to get them.

Rod length affects the maximum piston speed, and can have effects on how the engine breathes from a airflow standpoint. Can also effect the amount of ignition timing needed based on dwell times.

Rod length is almost irrelevant, I'd prefer to have a decent piston than the longest rod possible.

Doesn't a short rod put more side pressure on the piston and block causing ring failure, don't some engine builders call it a bad rod to stroke ratio.

I dont know if it will cause ring failure but your piston skirts will take a beating.