i have a 350 truck block i would like to use for my boat. i have heard that a truck block isent all that reliable in a boat dose anyone know if thats true or not???
No i dont have marine heads. the P/O switched both block and heads over to truck ones and he had problems with valve seats on the heads. he told me to get the small valve heads out of a truck or marine heads and im woundering if i can go with truck heads or not what size i need if i can. this is for a fresh water boat only since thats all i have here in MN that i will go to
the block and heads for trucks are the same as marine. what makes a marine longblock is the brass core plugs and stainless steel composite head gasket, and a specific marine cam.
you just have to know which engine year you have so you use appropriate parts.
oh my goodness i have been looking around and saving my money to buy a marine motor for nothing!!! that rocks!!! now i have all the money i need for the rebuild!!!! sweet!!!!!!! thanks guys. but i still have 1 ??? why did the P/O think he was having problems with the valves if the heads are the same any ideas???
if you use small valve heads on a 350 block you have some serious issues. Compression goes too high due to the small combustion chambers. The bore is then larger than the chamber so it overhangs. Put 350 heads on and hasve a reputable shop install valve seats if necessary.
Hey guys...
Just to be accurate... don't most mercruiser 5.7 and 4.3 heads have hard exhaust seats. I recall some but not all truck engines have them also. I think its for moisture in the boats, heat from towing in trucks.
Hey guys...
Just to be accurate... don't most mercruiser 5.7 and 4.3 heads have hard exhaust seats. I recall some but not all truck engines have them also. I think its for moisture in the boats, heat from towing in trucks.
there is a misconception about early vortec heads where the factory had re-worked many castings with a pressed in valve seat. As Bond-o chimed in, they are all hardened.
Yes i understand that all seats are at least induction hardened !!! :facepalm:
There is a specific truck vortec head that has an hard insert seat in the exhaust. I have seen them with my own eyes at a local machine shop. They have a shelf full of them because supposedly they don't flow as well as the ones without the insert. Once a customer gets them torn down and realizes what they are they don't want to use them. I'm guessing the factory cut and blended the bowl different while installing this seat.
there is a misconception about early vortec heads where the factory had re-worked many castings with a pressed in valve seat. As Bond-o chimed in, they are all hardened.
I found the article where i got some of this info...
Quote from article...
" The L31 Vortec comes in two different casting numbers, 10239906 (#906) or 12558062 (#062). Originally, the stock #906 casting head was available in two versions. One version had an Inconel exhaust seat with single angle valve grind and was available on 1 ton trucks. The other version was the traditional three angle valve grind. Other than that, the #906 is the same as the #062 head. "
