will a squarebore to spreadbore adapter plate effect performance?

kevincave

Petty Officer 3rd Class
Joined
Apr 25, 2009
Messages
87
Re: will a squarebore to spreadbore adapter plate effect performance?

Sorry but no. You have to remember this is not a race car, it has no transmisison and you can't bring the revs up and drop the clutch. A Marine engine has to develope a ton of torque from a dead stop. When you drop the hammer and go WOT the velocity of the fuel air mixture drops DRASTICALLY. The engine has almost no vacumm at that point. Unless the intake manifold, any spacers, and the carb are all matched and setup properly you will have nothing but trouble coming out of the hole.

isnt that the same thing a drag car does, say with a power glide two speed auto trans?
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: will a squarebore to spreadbore adapter plate effect performance?

Sorry but no. You have to remember this is not a race car, it has no transmisison and you can't bring the revs up and drop the clutch. A Marine engine has to develope a ton of torque from a dead stop. When you drop the hammer and go WOT the velocity of the fuel air mixture drops DRASTICALLY. The engine has almost no vacumm at that point. Unless the intake manifold, any spacers, and the carb are all matched and setup properly you will have nothing but trouble coming out of the hole.

Not to try to argue with you or anyone for that fact, but a dyno. has no trans eather and thats where we all the testing. as a matter of fact it has a "water brake". and all the data is read by computer from idle, WOT at 1000 rpm to WOT at 7500 rpm.
as another poster said this could go on for ever with no difinite results.

No i raced cars.

Just put the spacer on. its not going to give you a noticable drop or gain. then when you get the money for the right one, you have your own results for a comparison and can post them.

I can say one thing for sure, that a Holly of any kind (marine or other) will give a marker performance gain of the that Edelbrock P.O.S.
that is a Carter revamp from the 60's and there is a reason that they are out of business.
 

wca_tim

Lieutenant Commander
Joined
May 28, 2007
Messages
1,708
Re: will a squarebore to spreadbore adapter plate effect performance?

If I understood the op's question. He was asking if he could do it temporarily and not have problems - not whether it would make an incremental difference in performance. It won't be a problem.

I also think that we make a lot of blanket statements about what is needed in a boat engine, etc, etc, etc... without fully considering the situation (ie need tons of torque down low, etc...). My current small block engine has a single plane intake, 200 cc runner heads and is propped for top end. I can pop a heavy slalom skier or boarder out of the water with under half throttle no problem... even with an adapter plate in place between the pos edelborck carb that's been on it most recently and the square bore manifold I've had on it... If there's anything that I've learned from the conversations with the guys in the machine shop I use - Some conventional wisdom, may not always be spot on.
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: will a squarebore to spreadbore adapter plate effect performance?

Too true, beating a "dead horse" here! :rolleyes:
Just do it! ;)
 

lime4x4

Lieutenant Junior Grade
Joined
Apr 25, 2007
Messages
1,040
Re: will a squarebore to spreadbore adapter plate effect performance?

Well i dropped the 350 vortec engine.Using the adapter. Idles nice and smooth has good transition of power .Boat use to take 1 min 20 seconds to plane tonight it came onto plane in 31 seconds. I'm not cing and ill effects from using the adapter plate
 
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