Gen VI 454 Engine Build Questions
 

G'day all,
Great site with amazing tech support!! Now I've come up with my own problem in hopes of some assistance...

I'm building up a Gen VI 454 for a Stinger 222 and I am stuck on a few issues that are of concern.

My first issue is the heads: I have the Vortech 7400 heads which have just been rebuilt with uprated valves etc but are they any good to start with? I have read elsewhere that they will only flow up to about 4700rpm? Is this correct?
Second issue is the venerable Cam selection point. I am currently looking at the Crane 741 to match with ~10.3:1 comp, Strip Dominator single plane intake and a Holley 850 Marine carb. Exhaust is a custom stainless (wet) high flow with built in risers / elbow so they have a relatively short runner / collector length.

Is that cam any good for my set-up?
Intake @Cam 359 @Valve 610
Exhaust @ Cam 372 @Valve 632
Rocker Arm Ratio 1.70

Or would this Lunati Option #60203 do better?
Intake @Cam 268 @Valve 542
Exhaust @ Cam 276 @Valve 554
Rocker Arm Ratio 1.70

I've also been looking at this:
Intake @Cam 293 @Valve 629
Exhaust @ Cam 303 @Valve 612
Rocker Arm Ratio 1.70 with 114 deg seperation.

Any help or straight advice would be greatly appreciated!
:evilb:

All depends on what you want out of your boat, or the type of use. All out speed, cruis'n with the family, tubing/skiing....etc.

Best person to contact would be site member rmbuilder aka Bob Madara, of Marine Kinetics at 585-654-8583. rmbuilder has designed cams for countless people on this site and can tell you what cam/head/intake combo would be right/best for your needs. An rmbuilder cam spec'd specifically for your needs/application won't cost much more than an off the shelf'r.

that intake is not very good for boats, the rpm level is way to high and you will never get there with out destroying the drive quickly, need something like a performer rpm air gap, you need to keep the max rpm between 5500-6000...my thoughts Rob

Okay thanks! I've re-arranged my lofty aspirations somewhat, I'm mainly used to building car engines and the motor for my Sanger flat bottom! My guidance so far says I should get myself a dual plane manifold, an ~850cfm carb and run the #741 / 731 Crane cam to do what I need.

I've found a Performer RPM Air Gap, so I'll grab that. The Crane cam seems like it should do the trick without issues and I've found a few available down-under. Now all I need to find is the right set of exhaust for the right price. I'm looking now toward GIL or IMCO, Lightning make a nice set but I'd need a second mortgage!

Anyone have set they would like to dispose of? I can help!!

Thanks again,
John.

I've got a new set of Lightnings I paid $2400 for. I'll take $1800. Black powdercoated, probably have less than 2 hrs. on them.

That's Brilliant!
Can you post some pics or just email them to me at [email protected]
I have no idea about postage, I've been told via ebay that it should be do-able for less than $200 but we shall see... How much do a pair of Lightnings weigh anyway?

Another random question, anyone know if there are any fitment issues with Vortec heads and inlet manifolds? Also what jets would be best in a BG Demon 850cfm carb with a Crane 741 cam? What psi should I get with around 10:1 comp?

The more I think about it, the less I know about big blocks!!! :party-smiley-004:

Kennyo . Email or call me about those headers..

Chris
[email protected]
727-599-1941