Holley 450 vs. 600
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=1998
Printed Date: November-26-2024 at 7:48am
Topic: Holley 450 vs. 600
Posted By: stang72
Subject: Holley 450 vs. 600
Date Posted: July-04-2005 at 6:51pm
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Have a question for the holley guy's.On the 4160 models...should I be using 450 cfm or 600 cfm..1972 ford 302? I believe mine is a 600 (remanufactured from allcarbs)recent purchase..I can't seem to get it set up right.Float levels look good. I adjust the screws back to where the engine surges(lean) and than turn them out to where it sounds good...set the idle @600-700 rpms in neutral..it wants to die when putting in gear and is hard starting.It is beginning to PISS me off!!!
What is the difference between the two??? I have a 600cfm on my other boat...351 ford and if performs like a champ! And of course...before someone throws it out there..no , I don't have a wedge plate on either boat!!! Thanks Gary ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Replies:
Posted By: Bob's2001
Date Posted: July-05-2005 at 2:47am
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I had a similar problem after carb rebuild. The base gasket was not wide enough and allowed a vacuum leak between carb base and manifold.It looked wide enough but after starting up it would suck air. It was Mr Gasket for Holley. A new wider gasket cured the hard start and dying problem. You should be able to run a 600cfm carb on a 302 ------------- Bob Ed 83 2001 |
Posted By: stang72
Date Posted: July-07-2005 at 11:34am
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Yep...did had a gasket leak...better now...not quite there! I need to check for other leaks...pcv valve etc.
Thanks! ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: pmt2234
Date Posted: July-07-2005 at 4:02pm
| Maybe try using a vacuum gauge to set your idle mixture for maximum vacuum. When I switched from the ear method to the vacuum gauge method on my 84 2001 w/ a 351W, 600cfm Holley and a wedge plate, my in and out of gear idle was vastly improved. Now going in or out of gear hardly changes my engine rpm. |
Posted By: nms1991
Date Posted: July-08-2005 at 1:06am
| You are over carbed you will posssibly run rich at mid to wot and burn excess fuel. PCM normally used a 450 cfm carb on the 302 and it performed perfect as long as the other systems were in good shape. And there are a lot of boats running great out there without the wedge plate and a holley carb, but the weber/edelbrock/carter carb does need one on the older motors that are on a severe angle. |
Posted By: stang72
Date Posted: July-08-2005 at 4:34am
Oh great! Burning excess fuel with todays gas prices...ouch!  So the 450 is a better choice I take it.How big a difference is there?
Anyone want to swap me? This week end a buddy is going to tune her up and add some new ignition parts(very needed)...and we can see how it runs! If it's not all there..then I am going to be wondering...450 ???? and if I am lucky...maybe he will have a vaccume gauge too! 
Thanks GH ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: stang72
Date Posted: July-09-2005 at 1:59pm
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Looked again for vacuume leaks at the gasket(carb base)...sucked a fair share of cig smoke...theres air moving!Plugged the leak for a moment and my idle dropped..it fired right up each time...that gasket is not wide enough!
Big thanks! case solved!Damn those simple things should be checked first! (hold on a sec...door bell)UPS!!!!Dis inboard marine!!!!Parts! new ei ingnition!!! Gotta go! Gary  ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: stang72
Date Posted: July-10-2005 at 2:47am
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Ran it on the lake today( all day)...burned a tank of gas and it ran great...started easy every time. Bob Ed...you were right on the money! Even the idle is where it should be!!!!!
Smooth @ 600 RPM's....Happy camper I am (well if I camped much that is). 
Thanks! Gary ------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: Bob's2001
Date Posted: July-12-2005 at 2:35am
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Glad you had a good day. It took me a week to figure that out! Now if I can get a little time off work I'll go burn some gas myself ------------- Bob Ed 83 2001 |
Posted By: Guests
Date Posted: July-14-2005 at 10:23am
| I have had vacuum leaks when using new Mr. Gasket carb gaskets. A Fel-Pro cured the problem. |