camshaft selection

[tsiguy91]

Hello everyone,
I'm building an 87 chevy 5.7 to a 383 stroker. I have an I/O with a volvo outdrive and water fed exhaust manifolds. I'm going with a set of vortec heads also. Because of the vortec valve springs I am limited, (from what I read), to .480" lift max and limited duration with the wet exhaust due to reverb. I'm looking for camshaft recommendations.
Thanks guys,
Marty

 

[Don S]

Re: camshaft selection

Welcome to iboats, might try doing a search over in the Mercruiser forum, that same question comes up once or twice a month.

 

[tsiguy91]

Re: camshaft selection

Ok, thanks. I did a search in the volvo section, but couldn't find much

 

[Don S]

Re: camshaft selection

Ok, thanks. I did a search in the volvo section, but couldn't find much

That's why I said do a search in the Mercruiser forum.

 

[tsiguy91]

Re: camshaft selection

Once again, thanks I got your message loud and clear Don.

 

[Scott Danforth]

Re: camshaft selection

There are a couple of threads that you can read

http://forums.iboats.com/showthread.php?t=503800
http://forums.iboats.com/showthread.php?t=524489
http://forums.iboats.com/showthread.php?t=538908

have your heads checked by the local machine shop. either have the guides cut or buy beehive springs. however going the route of having the guides cut will be much much cheaper.

as for the cam, your engine is similar to my '88, so your limited to either a flat tappet or retro roller. the duration and lift will be determined by your exhaust, size of your boat, normal operation of the boat,etc.

 

[tsiguy91]

Re: camshaft selection

Great info Scott, thank you. I'm considering not using my Vortec heads now, I have 12cc dished pistons for the stroker set up and with the 64cc chamber vortecs I will be around 10:4 to 1. Wich is sounding a little high, especially with the smaller cam I'll need to run. What ratio are you runnin?

 

[Scott Danforth]

Re: camshaft selection

I left the stock long block. originally 9.4:1 with the 76cc chambers. will be running about 10.4 myself, however I will be running 91 octane.

 

[prosndinc]

Re: camshaft selection

If you are building a new engine, changing heads and cam don't even think of cheaping out on valve springs! Spend a few bucks and get the proper springs that match the needs of the cam.
Call Comp Cams tech support line with all your engine spec's they will get you the right cam with the proper overlap and duration profile to avoid reversion.

Good luck

Charlie