90nova

Noticed my seaboard engine idling badly and lean popping while planning boat off. Checked for a vacuum leak and found part of intake gasket missing in #5 intake port. Just purchased the boat and did not do the motor work. Looks like the intake ports on the heads extend higher than the intake. Guessing these are large port vortec heads? They have dual pattern bolts for old style and vortec style intakes. Motor currently has Bow tie marine z28 intake. Would switching to a vortec intake correct this? The ones I looked at seemed to match the ports of these heads better.

Thanks[ATTACH=CONFIG]527983[/ATTACH][ATTACH=CONFIG]527984[/ATTACH]

f_inscreenname

Have you matched up a new intake gasket? Looks like it slid down some during install and was just hanging on until it let go.

SB

iTrader: (1)

It's a Vortec replacwment head from RHS - the ProTorker.. As you prob now, Vortec intake runner's are raised.

Reason for the dual bolt patterns are for Restricted Rules Racing with rules that state cast iron intake. Not too many cast iron 4bll intakes out there for Vortec's. Well, there are two, one sucks, and one is a secret (shhh) and is some $$$$ if I tell you and not a complete bolt on out of the box.

Anyway, if keeping the standard intake you'll have to see if it has enough metal above the heads intake port to seal.

If it does, you have to get different intake gaskets. You can get a Felpro trim to fit or you can try to find a gasket for Raised Runner 23° Heads (AFR/Brodix made some raised runner convention neads) .

Vortec intake manifolds and gaskets will obviously solve your issue but it will be a chunck of change. Manifolds, bolts, and gaskets are more than regular 23° small block stuff.


Edit in: if you go the Vortec intake route and if your current intakes are the high rise Bowtie cast iron intakes, you should get $100-$125 for each intake if sold used. Restricted Rules Racers and some boaters look for these.

90nova

Thanks for the fast replies! Think I'm going to swap over to a vortec intake. There is definitely a gap between the outer edge of the intake and the intake port and port shapes look different between them. Don't want to rely on the gasket to cover the hole and have this happen again.

FIXX

iTrader: (2)

you might be able to get away with 1206s-3 or 1207 brodex style gaskets..made bty felpto..

edit make sure you plug the old holes in the head if you do go with the vortec intakes..you want the rpm air gap style..

90nova

Thanks, I was planning on purchasing the performer rpm air gap. $280 shipped isn't too bad at all. Especially if I can sell my old intakes to recoup some of the cost. I was wondering if I needed to plug the old bolt holes, noticed the vortec holes had bolts in them now, I will look for some plugs now to do that. Thanks again for the help.

SB

iTrader: (1)

If the cast iron from your intake doesn't cover them, the gasket won't seal there onit's own.

You are doing the right thing.

Good find and good for you to ask when you are not sure.

That's what forums are really for.

BTW: If you get the GM style intake gaskets make sure you get their bolts too. Bolt torque is low, like 12ft/lbs Follow the instructions exactly.

Felpro makes a standard material gasket. You can use normal style bolts and torque to typical torque values.

Writing the above made me think of one thing, before you order parts - I'm not sure what thread size/pitch the Vortec holes are on your heads. If the GM Vortec bolt hole size which I'm not sure if the same as the old heads or not. Good time to check them now.

FIXX

iTrader: (2)

yes,,and the holes are wet,,they most likely go into the coolent passges so you are going to have to use some ritestuff on the set screws and let it dyr over night b4 you set the intaes on..and listen th SB also on the bolt torque..i use blue loctite on them because they come loose on vehicles so for damm sure they will come loose on boats..also always start low on the torque and when you reach 12 ft lbs go ocwe all the bolts several times..i torque the bolts in inch lbs just to make it easier..