I need new heads. My brother in law can get me a very good price on GM parts so I'm not interested in other brands. So, I am trying to figure out what the difference is between the Vortec, Fastburn and ZZ4 heads.

Vortec are the cast iron heads that GM started using in '96. They are cheap have better flow than old school heads but require a new intake manifold to match the heads. I have also heard they are not good for cams with high lift. I'm unsure of what cam is currently in my car, but doubt it's too aggressive for Vortec heads.

Fastburn are aluminum versions of Vortec heads?

ZZ4 are aluminum and ???

I don't know much about heads, except that I'm replacing a set of '69 double hump heads because the cast iron has broken off at a bolt hole and I can't get my intake to seal across the back wall because of it.

What do you guys think is my best option?

 

Lucky guy

Do you have the casting number on your current heads? They're likely 64cc chambers, so you'll want to stay there or less to keep your CR. You also likely want to stick with the same plug type (angled/straight) if you have headers.

Everything you need to know is in the GMPP catalog here:

http://www.gmperformanceparts.com/_r...09_Catalog.pdf

...but the Cliff Notes version for street heads is:

12556463: ZZ4 "Fast Burn" heads; Basically an L98 Corvette head with upgraded springs. 58cc chamber, so you pick up about .6 CR. 163cc intake runners means flow about the same as the Vortec design that they were an early version of. Generally, I'd pass on these heads. I posted more information on these here.

12558060: Vortec heads; probably the best street head out there for warm 350's and very mild 383's. Lift limited to .475 without a spring change. Requires a Vortec manifold.

25534421: Bowtie Vortecs; upgraded Vortecs with some interesting flow numbers. Will fit "standard" intake manifolds. I haven't worked with these, but they'd be interesting in your application if you're willing to do a cam upgrade at the same time. 185cc intake runners, with 225 runners (way too much unless you're going mondo) under 25534446.

12464298: Fast Burn; top of GM's list for a street head. With 210cc intake ports, need gears and a fairly hot cam to make these work.

I don't know what kind of a price you're getting on the GMPP stuff, but the easiest and fastest replacement would be one of the Stock/Replacement heads such as the World Products S/R or S/R Torquer heads, Dart Iron Eagle or similar head. You may want to back up for a second and think about what you're trying to achive - do you just want to replace what you've got, or upgrade while you're swapping heads?

 

I've used the vortecs on several engines. Had them on my stockcar, which were modified for more lift.....ran to 7000 RPM regularly. I currently have them on my 406 in my '77 only have about 100 KM (60 mi) or so on them.....so far I'm impressed. Some guys on here don't like them because they dont have 210 cc intake ports, and you have to buy an intake manifold, but if the price is right for the heads,spending a few extra beans on a intake wouldn't be too hard to take.
Vortecs make good power....not as good as AFR210's, but its up to you how much money you want to spend.

 

Another pair of double hump.