Vortec Heads or not?

[jordelheide]

I have a 95 Mercruiser 350 Mag EFI (SNf215955) that needs to be replaced do to the first owners neglect (cracked block). Do i have vortec heads? Also I have found a motor built by ZigourasRacing. Anyone heard of them? Heads have been modified with a 3-angle valve job, and all new racing springs. A high performance marine cam was installed, along with high compression pistons, and a whole bunch of other goodies. All external engine bolts are brand new stainless steel bolts. Would this be a good way to go? It would be cheaper than having mine rebuilt. It does have a 30 day warranty.

 

[jlshields]

Re: Vortec Heads or not?

Look where the intake bolts to the head. Vortec use four bolts. Old style use six. Usually if it's carburated it's old style.<br />john

 

[Boomyal]

Re: Vortec Heads or not?

As far as I know, VORTEC was introduced as part of GM's multiport sequential fuel injection system that first appeared in 1997.

 

[rodbolt]

Re: Vortec Heads or not?

Hello<br /> Look at the hopped up motor. oh and ah over it. then run like hades. stay away from the hop ups. if you cannot repair it then stay away from it. it turns into a frankenstien nightmare. there are many places that will giv a 1-2 year warrenty on a rebuilt unit. the problem with increased cam lift is overlap will increase. now you will have to increase your X diminsion for the riser height. if you increase power much you will have prop and possibly gear ratio issues. if the motor detonates a oiston I bet you warrenty will be void. most marinas including mine wont work on any motors that have been modified unless thge mods were performed at their marinas. I am not going to spend time trying to figgue out what parts we have and what is wrong at 75 dollars an hour. no fun for you or me. in a car you have gear selection to compenstae for engine load. on a boat you dont. and on a boat you usually cannot hear the detonation like you can in a car. <br /> Good luck and keep posting

 

[bluewater19]

Re: Vortec Heads or not?

General motors didn't make the vortec heads until 1996. These casting were originaly found on the L-31 truck motors. They are a standard flow version of the Famed LT-1 corvette head from made from 1992-1997 the only difference between these heads are corvette heads are aluminum the truck/marine heads are cast Iron. and the cooling passages are different as the vette cools the heads first then the block and the truck cools the block then the heads. These are the best bang for buck in cheap HP increases. They flow better out of the box than the legendary GM performance parts bowtie heads.The vortec heads also have a different intake bolt pattern with 2 bolts per corner instead of six bolts per side. I have seen the motor you are talking about on e-bay and that thing should be a solid upgrade in horsepower over your merc 350mag. These guys build offshore motors for a living and If I was going to buy a performance marine engine they would be on my short list.check out how many motors they have sold. They also offer an extended waranty on these motors. Also call local Hi perfomance machine shops in your area and see what they would charge to do a marine rebuild on your motor. I would trust a machine shop that rebuilds alot of motors over a marina in most cases. Just make sure they are experinced in building marine motors.

 

[jordelheide]

Re: Vortec Heads or not?

Ok thank you all for the imput. I have concluded that I do not have vortec heads. Thank you. <br />I do seem to be getting mixed signals about the upgrade. Rodbolt I think I understand what you are saying. How long could I expect a motor like this to last? An is the real problem finding parts for it when it breaks down? How much will the power increase affect the whole situation?