Re: Engine replacement question
Do I need a special intake? I read that some intake have provisions for water passages and what not. What do I get?
-barry
All SBF intakes have provisions for water/coolant passages. This is why you do not want to run aluminum aftermarket intakes in saltwater. If you are sweetwater use only, you can do it. Otherwise stick with the oem 2 or 4 bbl castiron intakes.
If you do go with the aluminum, stay with the Dual plane Edelbrock Performer or equivalant. Do not step up to the Edelbrock Performer RPM intake or any of the single plane intakes. They move the power curve too far up the rpm scale and your boat will fall flat on it's face on acceleration. All of the aftermarket intake mfgr's will list the effective rpm range for their various manifolds. If you go aftermarket, you want to stick with the ones that are rated from idle to 5000 or 5500 rpm.
I would also say that better breathing aftermarket heads would be a waste of money. Your motor will be limited by how much exhaust can get out through very inefficient marine exhaust manifolds. OEM heads will handle as much, and possibly a little more than you can get pushed out the stern.
On carburetors, the very most proper upgrade for your 302 to a 4bbl, would be a 500 cfm version. Unfortunately the only one that makes a marine 500 cfnm 4bbl is Holley and they are nigh unto impossible to find used. You'd have to buy one new.
Factories who put 4bbls on their motors usually always used the generic 600 cfm carbs because they were cheaper. If one of those is set up (jetted and metered) for the 302, they will work, they are just not ideal for the somewhat limited airflow of a 302 marine application.
All that being said, they can still provide a signifcant increase in power over the 2 bbl, w/ stock heads. Just make sure any 600 you get is set up for the 302, not a 351 or 350, otherwise you would be overcarbed. Holley uses 'list' numbers, stamped into the air horn, to identify what motor they were set up for. If you find a used one you can call Holley and ask them.
Oh, and if you go to a 4bbl, learn throttle discipline. While 4 bbls, running on the smaller primary venturis, are as economical as a 2bbl, you get constanly happy on the throttle and you will pay.
If you do go to the aftermarket 4bbl intake, you will find the suitable Edelbrock to be the least expensive and the easiest to find used. Here are a couple of links.
http://cgi.ebay.com/ebaymotors/Parts-Accessories___Edelbrock-performer-289-Ford-8-2-deck-intake_W0QQitemZ180316851899QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItemQQptZRace_Car_Parts?hash=item180316851899&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318
http://cgi.ebay.com/ebaymotors/Parts-Accessories___EDELBROCK-PERFORMER-289-INTAKE-2121-260-289-302-FORD_W0QQitemZ180316848141QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item180316848141&_trksid=p4506.c0.m245&_trkparms=72%3A543%7C65%3A12%7C39%3A1%7C240%3A1318
