New to the board,thanks.
Im building a virgin 1971 350 4 bolt for a fishing boat.
No high horsepower needed here,just an efficiant engine.
Im going to run a set of brand new(99) Vortec heads on it.I understand the int. manifold must be changed,so thats not a problem.
I have the heads,rockers,pushrods from the Vortec engine that will be installed on the early block.
Are there any suprises involved here?Push rod length,lifter length ect?
I mite pop up some different questions soon about this swap.
Thanks for your time & space,
Troy

The pushrods probably won't work if it is from a factory roller cammed engine. However, stock replacement pushrods for an earlier sbc will work just fine. You will also need the centerbolt valve covers from the vortec motor as the old style won't fit. If you are doing a cam upgrade be cautious going over about .450 or so lift as you could run into retainer to guide interference. You will love these heads!

Troy,
The only problem I see is that if the engine is river water cooled, you might have problems with an intake. I dont know if any cast iron manfolds are available for the vortec heads, and the aluminum ones are terrible on a marine engine due to the corrosion. If you do use an aluminum manifold, I would see about getting the water passages coated by Jet Hot or something similar.
What would really be neat would be to see if you can find a late model Mercruiser EFI setup to put on it. A lot of performance shops take them off and sell them when installing blowers etc. You should be able to find one for a reasonable price.
Have fun !

Coolant on this engine is done thru a heat exchanger,so saltwater corrosion is not a problem.
I have the centerbolt valve covers,but my only concern is pushrod length.A guy told me that the later Vortec blocks have the same deck height as early blocks,so pushrod length *should* be the same.I guess I can do a physical check.
I'm planning on running a Comp 260H,Edelbrock Vortec manifold,HEI,650 Edelbrock carb.Does this sound like a good combo?We are looking for fuel efficiency as well as a power increase with these heads.
Thanks!

If you need a cast iron manifold, one is available. It is a marine piece and most online GMPPs houses catalog them.

as stated earler push rods are shorter on roller cam vortecs, you also need to run the factory vortec rockers or guide plates