What's the main difference between Fastburn heads and vortec heads?

 

I assume you are taking about the Gm fast burn heads. The Gm fast burn heads have 62 cc chambers and are aluminum. It is not recommended that you port them because it can change the way they perform. I think you can port one little part of them though. The GM votecs are cast iron and have 1.94" and 1.55" valves. They also have 64 cc chambers. They can be ported a lot to make serious gains (especially on the exhaust side). The only problem is that they need to be machined to accept a cam larger than .480" lift. However, some simple machining, and port work make these heads capable of supporting 400hp with ease.

 

Not to jump into a conversation, but I recently purchased a set of seriously worked over Vortecs from a machine shop in Arizona. Was kinda a goofy deal with me sending the money and not hearing from them, so got the lawyer on the hotline, made some calls and boom they showed up...anyways I heard these iron heads flow better than the ole double humps of yesteryear and these heads were set up for a .600 roller, but he had to do some maching, change springs and since he was at it asked if I wanted 2.02/1.60 valves installed. They also did really nice port work throughout and were supposed to flow test before shipping but I ver got a sheet. Just dropped them off yesterday at the local head shop guru's to have them checked out and flow tested so I have some numbers about what these heads of mine are capable of now over out of the box. Another reason I wanted them flow tested was to see if going 1.6 on the intake side is going to be needed. They told me that unless the heads are still asking to flow more at .600 lift the 1.6's will not hed any gains since the flow is all done. right now the will be flowing a Lunati soild .530/.544 cam so we'll see what these babies can do with a mild motor.

 

Vortec heads... are factory equipitment for gm's trucks. The Heads from the "L31" engine code trucks are the ones most folks use on their hotrods.. factory 350 truck engines.

They have great flowing intake ports, alright flowing exhaust ports, semi raised runners, a High quench heart shaped combustion chamber, and typically come off the shelf at 63 cc's.

In off the shelf form, they are the best flowing, performing production GM head for their pre lt1 small blocks.

They even hold up well against aftermarket heads.

Things you'll need with them.
New valve springs.. the factory springs are woefully inadequate for nearly anything.
a vortec head intake.
centerbolt valve covers.

as far as work to the heads... they do very well with bowl work, but you want to stay out of the ports.. unless you are reshaping nearly everything and hogging them out.. you will be dissapointed.

The stock valves work well. if your runing a standard type valve train and not roller lifters you'll be likely to need self alignign rocker, or opt for studs and guidplates.

Dollar for dollar the best heads out there.



The Fast burns are the GM performance aluminum race version.
larger vavles.. 2.02/1.6 valves compared to the vortec's 1.94/1.5
they ahve better exhaust ports out of the box. but the intake is roughly the same. same great heartshaped ports and high quench chambers. same intake bolt patern, and hight
But the intake ports CC around 190-200 if memory serves me.. instead of the vortec's 170

More or less the same thing with hogging them out.. valve train sa,me thing.. they really are a very similar set of heads, jsut aluminuim with more voluminous ports.. really set up for bigger cube engines and higher compression.....IE a race head.. rather than a truck head.

If it's a race car and you want to run better than mid 11's.. you'll want the fast burns.. street strip car faster than the low 12's... you'll want the fast burns.

 

I have everything for a complete vortec swap, heads that have been worked over-port job, 2.02/1.60 valves, guide plates, screw in studs, springs to .550 lift, can use old style roller rocker-DO NOT use self-aligning rockers, new cast/polished aluminum valve covers and matching air cleaner, ALL gaskets needed to do head/cam swap. new .015 head gaskets, new in box Lunati solid .533/.543 cam 102/110 duration and new Lunati solid lifters, Edelbrock air gap dual plane intake with new ARP bolts. I have enerything sitting right behind me brand new for a COMPLETE top end change, just add oil and break in cam. Combo was put together for a 450hp flat top 350 engine with 10.4:1 compression since these Vortec heads take less timing than old school heads you can get away with a tad more compression on pump gas. Found out wife is pregnant with the 2nd, so of course change of plan. ALl parts brand new still in the boxes ready to go, can take pictures-actually will be putting on e-bay soon anyway. Total for everything $1200.00 plus shipping. Have $1700 invested in everything I'm getting rid of.

 

They're listed at 64cc's yet a lot of them are measuring out to 62cc's.

 

Check your facts on the fast burn heads. These heads are equipped with light weight LT4 2.00" intake valves and 1.55" exhaust valves. This information was obtained from pg 47 of the SDPC 2000 parts catalog.:rockon: :rockon:

 

jpk91rs is right about the Fastburn valve sizes. I have these heads and that is what they are.

 

One note of caution for anyone using the fastburns, double check the rocker studs. I had 2 of them come loose on me, and I bent a pushrod. Could've been SOOO much worse. Sounded like the bottom end was coming loose from inside the car, but then it shut up and was running on 7 cylinders! All better now, after pulling all the studs and putting loctite on them!

What intake and gaskets are people using on their setups? I have a the edelbrock performer vortec, and HAD the Felpro gaskets that are a thick "paper" type gasket. Well, the gasket slid down and caused a bad vacuum leak. I replaced them with the OE style plastic gaskets (That we replace all the time on customer's cars) and they BARELY fit the intake. I can see a bit of the gasket at the top of the intake. I haven't figured out if it's the intake, or the heads, but something just isn't right! I'm pretty sure it's the intake.

 

If I remember correctly I use the GM intake gaskets for the vortec heads.