355 Vortec combo need cam advice

rodknockracing · Newbie Joined: 18 Aug 2011 Posts: 1 144.24 points

Hi i am new looked like a good site so i joined. Now on to buisness. I have a nice little small block going together for my mud truck. It is a .030 over four bolt main with forged crank and rods and about 12.0:1 compression with my vortecs.I am building this with vortec heads because the class i run in i must use factory heads.Now i need a cam solid flat tappet and i just dont know what to use, i know flow drops after .500 but there has been some porting done. What is your suggestions? ... I would go roller but my budget just doesnt allow thanks in advance

Big Dave · Posted: Fri Aug 19, 2011 6:34 pm Post subject:

Welcome to the site!

Vortec heads have a valve lift limitation of 0.520" and that is after machining the heads to accept a standard SBC valve spring by cutting the valve spring pocket, the cast in head push rod guide, and the valve stem guides oil seal seat in the head to reduce coil bind at 0.520" lift.

Also most Vortecs flow better without any port work as most pros who had twenty or more heads to experiment with first, could only get a 3% improvement in flow numbers after throwing everything they know at these heads (they had a friendly little competition involving a bunch of pros vying for bragging rights).

Big Dave

af2 · Posted: Fri Aug 19, 2011 6:34 pm Post subject:

I have run and liked the Isky.
The Z35 for my Vega with a 331/ 4 speed, That I sold in 1985.
The Z70 that is still in another 33 Willys street car at 327 ci.
The Z65 that was in a 34 Ford with a T400 and also 331 ci.

They were and will be a good cam to start with depending on the RPM you want to run and the springs you are willing to put in there.

squeeezer · Posted: Wed Aug 24, 2011 8:28 pm Post subject:

[quote="
Also most Vortecs flow better without any port work as most pros who had twenty or more heads to experiment with first, could only get a 3% improvement in flow numbers after throwing everything they know at these heads (they had a friendly little competition involving a bunch of pros vying for bragging rights).

Big Dave[/quote]

these heads are not "immune" to porting
im glad Dave you said "most"
these heads need porting due to the discrepencies of flow intake to exhaust
you can port the heck outa these things and end up with a head you can barely recognise......better know someone who knows what they are doing though

squeeezer · Posted: Wed Sep 07, 2011 8:14 pm Post subject:

hows the project goin????