350 mag troubles, roadtrip??

[marcdups]

Hi, just wondering what your thoughts are, I tuliped a couple of valves on a 94 350 mercruiser due to a bad thermostat i have determined, could find nothing else wrong with the engine, cross hatch still on the cyl walls all but one minute score on #1 cyl, valves tuliped were #1 and #5, have a set of vortec heads and a different highrise intake to match, do you think I will have problems with the comp ratios due to the chamber size or if not what hp gains am I looking at?? Thanks for any imput.

[Rootsy]

Chambers sizes are the same... your motor probably has the 217 ( there is another casting # also which is identical)castings which are 64 CC chambers... the vortecs have 64 cc chambers also...

measure the depth of the crown down from the deck at TDC so that you can get the correct head gaskets to set your quench distance...

what fuel do you run?

go with a performer (NOT RPM) style dual plane if you plan on retaining the stock valvetrain and the vortecs...

JR

[marcdups]

Rootsy, only 93 as most marinas carry it around here, and do add some Yamaha ring free at every fill up, which lately is NOT happening!! :bawling: , I just want to make sure I have the right combo if ever so slightly, the intakes I have are from merc and volvo high rise aluminium with brass inserts, although I am gonna change the block to close cooling, waiting on parts, heads are already on with merc gaskets so I think clearance should not be a factor, I hope :eek!: :eek!:, other than that I am waiting for a part # for an electric choke assy for the weber, the install holes are there and I have the wiring for it in my harness, but everything I kep getting are rebuild kits with no back plate and cannot find a back plate, other than that I guess it will be sunday before I can get back to it as the younguns are coming down this week end and I need to spend some time with them, won't be long before they will want one of their own, Donzi that is, thanks for all the input, Marc