Engine build and cam help

Automotive powered airboat discussion.
SthrnStyle3
Southern Airboat Member
Posts: 510
Joined: Mon Apr 06, 2009 6:41 pm
Location: Sanford, FL

Engine build and cam help

Postby SthrnStyle3 » Sun Mar 22, 2015 1:06 am

I'm in the process of rebuilding my stock 350 to get the most out of it and to work good with a 2:1 gearbox. The block has never been bored. I just tore it down this evening and it'll probably need to be bored a little. I'll have to see if the machine shop recommends turning the crank or not. I also bought a set of heads today. They are 14011043 bowtie heads with 64cc chambers, 2.02/1.6 valves and 184 cc runners. They may of been ported or polished because they are fairly smooth inside (not that I mind, seen as how I only paid $150 for the set! 8) ). I'm looking at getting the summit rebuild kit with the flat top hyperuetic pistons with four valve reliefs and probably a summit cam. I have an edelbrock performer dual plane intake and an edelbrock 600 cfm carb.

These are the questions I have:
1.) What cam would be best suited for my needs?
2.) What ratio rockers would be best?
3.) Will my 600 cfm carb be enough?
4.) What compression ratio and HP would I be looking at?
12' aluminum hull, 350 sbc w/ flattop Pistons and camel hump heads, side by side seating w/ double in front, 2:1 gearbox and a 78" whirlwind whispertip 2.0

loudmouse
Southern Airboat Member
Posts: 482
Joined: Tue Jan 22, 2013 3:20 pm
Location: Ocala Fl

Re: Engine build and cam help

Postby loudmouse » Sun Mar 22, 2015 9:56 am

U will be around 10.5 to 1 comp and the engine will need to be set up properly for it to live on pump gas. Quench needs to be tight.

I would use a hydraulic roller cam on a 108 LSA(or close). Depending on cam used, piston to valve clearances and springs would determine what ratio of rockers. Ur 600 carb will run the engine but will leave some performance unused. I would use a 750 Holley DP.
15' Alumitech deckover LSX TT Oxbox 84" JX 4-blade
Gas required Water optional :dontknow:
Built and Tuned by Me
14'X8' JW, Chevrolet 122CID LNF Turbo Engine, Ox box, 80" NGR 3 blade

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SthrnStyle3
Southern Airboat Member
Posts: 510
Joined: Mon Apr 06, 2009 6:41 pm
Location: Sanford, FL

Re: Engine build and cam help

Postby SthrnStyle3 » Sun Mar 22, 2015 11:36 am

Wow 10.5:1? When I use compression calculators I get 9.5:1 and summit says their Pistons with 64cc heads will have a 9.3:1 compression. I hope it's not in the 10's, I kinda want it to stay a pump gas motor..
12' aluminum hull, 350 sbc w/ flattop Pistons and camel hump heads, side by side seating w/ double in front, 2:1 gearbox and a 78" whirlwind whispertip 2.0

SthrnStyle3
Southern Airboat Member
Posts: 510
Joined: Mon Apr 06, 2009 6:41 pm
Location: Sanford, FL

Re: Engine build and cam help

Postby SthrnStyle3 » Mon Mar 23, 2015 2:27 pm

Well I dropped everything off at the machine shop.. The machinist said I'll be at around 9.5-9.8:1 compression and probably around 370hp. Anybody have a good recommendation for a cam grind?
12' aluminum hull, 350 sbc w/ flattop Pistons and camel hump heads, side by side seating w/ double in front, 2:1 gearbox and a 78" whirlwind whispertip 2.0


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