cooltoys61

I have a '96 7.4L from a truck and was thinking about buying another and building both for my boat. I have read these have great Fac. heads and with the roller cams and 4 bolt mains seems a good set-up. I'm thinking about stroker cranks but the whole attraction is the cheap roller motors. I have Dart single plane intakes and and aftermarket cam(specs are not handy but good mid-range )was thinking with raised compression to 9.5 and good intake,cam,Rev Marine exhaust, 450HP should be doable??What are your opinions on these heads and are there probs with these motors? If I run the cast crank can I run it to 5300 with stock or ARP rod bolts in the stock rods? Will the 6 Qt pan be sufficent? I've read it takes almost 6 grand to drain a 5 QT pan according to GM tests. Any help would be appriciated.

cooltoys61

The cam is the largest I can use without going to Adj rockers.
Chevy #12366543
224/234 @.05
527/544 lift.
110 deg centerline seperation.

Madmax

I have that cam brand new take out, plus a new set of GM lifters I will sell you if you are interested.... e-mail me offline at [email protected].

thanks.!

cstraub69@comcast

Problem is with the "peanut" port on the heads and the dart intakes I am assuming are Square port, it is going to be a hell of a mismatch. It was common use to put square port intakes on the old round port heads. ..but I don't think this is going to be a good set up. I would invest in a set of Merlin oval ports for the project and that would give you heads that down the line would be great for a pair of 496's.

I am a proponent of large oil pans for boats. . .go figure. . .you need a good deep sump pan with a minimum of 8 qts.


Cast cranks with stock rods and good bolts will run just fine with the power you are wanting. Budget 496 CID with the Scat cast stroker cranks make good choices also. This route would take a very mild cam due to the fact the CID would make the power.

Chris

cooltoys61

My darts are oval port to be used on rec for more torque or round. According to Dennis Moore these are great marine heads and 230cc large oval. The exhaust is the "peanut"(I think)because of it's shape but outflows all the other larger chevy exh ports. The Merlins are 269cc but since the Vortec is basically free with the longblock at the junkyard I thought a good valve job and mild port would do pretty well for under 5500rpm. Thanks for the ideas on the cast stroker,might be a good route for a mild stroker.

cstraub69@comcast

"Peanut Port" refers to the intake ports, they are very small compared to the old oval stuff. Your intake mismatch is not that bad then. . .port matching will work just fine and you should not have a problem getting 450HP.

Chris
Stef's Performance

Madmax

Vortec's are large oval port. I have them on my boat right now and they work well. Only prob is they have a very small chamber so the compression is around 9.00. Can only run 28-30 degrees total timing.....

On that note, I still wouldn't mismatch a rect port intake to large oval port heads. Edelbrock performer rpm works well with these heads.

cstraub69@comcast

Madmax,
I found what you are talking about, the L29 head that came out on the '97 GM trucks. Was not aware GM had changed. Thanks for the heads up. . .This head may work for stock truck pulling engines. . .

Chris

cooltoys61

OK. My intakes are for oval port. It will cover a Rect port if needed(extra material) and give better torque but is designed for oval port.

Pat McPherson

I have a set of 1999 Vortec heads for sale.
Shipping them is the problem though.
UPS wants as much as I want for the heads...