jacob brooks

I have a early 350 casting num# 3970010 1969-80 with heads cast# 33388-2 1974-80 76cc, Here is the problem, The center of my heads and intake manifold get hot enough to burn paint, burn oil, and discolor the head, push rods and intake. I dont have resticters or block offs in the riser port yet, I was concerned of doing that thinking it might make it worse on the heads. I don't have a over heating problem at all as far as temp of the entire system. Just the center of the head and intake. the initial timing is 8 and overall is 25. I have pulled the heads had them magnafluxed and surfaced. This engine is in my boat and the boat forum told me to try a chevy forum so here I am. I have built many motors and have what I considerd alot of knoledge of these motors, but I have never seen this it does not add up. The only thing I can think of is that the exhaust valves are not closing all the way of the cam is bad ? the motor runs perfect. please help Im lost!!! thankyou

mudmaniac

Do a compression test to confirm your thought on the exhaust valves.

jacob brooks

yea thats true I did already and it was 145 across the board. So I guess that rules that out. any other thoughts? thanks

mudmaniac

It could still be an issue with the cam lobes wearing and changing the duration.

jacob brooks

is there a way to determine that with out pulling the cam? I bought this boat with the motor in it and it was newer? who knows but I know the lifters looked good!

mudmaniac

You could pull the valve covers and measure the lift.

jacob brooks

ok thanks

cam3439

Did you ever find out your problem?

jacob brooks

no, but I think it might be my fuel pump starving my motor of fuel at higher rpms causing it to run lean. thats what im trying now, I have an electric fuel pump that is only rated for 2.5-3 gpm and a holley typically needs 4gpm and Im pushing through a fuel block water sep. Ill let ya know if it works

old dog

those port's are there for a reason on automotive and truck use they send exhaust heat under they intake to warm the fuel for better warm up when it is cold out .every small block with out the port's blocked off will cook all the oil and paint on them in that area .it,s the way they are designed for car's and truck's .you probably don't need them in a boat because you don't run it when it is cold and freezing out . put some aluminum or performance heads that the boat builder,s like .or dont worry about them .