Gm Fast Burn vs Ebay 200 Dart Pro 1 Copy

[Zing]

G’day I I’m building a 6500rpm 383 Sbc chasing maybe around 550hp
I know very little about the GM Fast Burn cylinder heads, but I’ve been offered a set of new old stock cast number ends in 7712 for the same price virtually as a pair of Ebay 200 Dart Platinum Copy Kmj Assault style alloy heads.
Both with minor porting and seat work which would be a better option?
Not much info over here in Australia on the GM Fast Burn heads?
I know I can get the Ebay Alloys to work but what about the Gm Performance heads in comparison?
Thanks for any info
Matt Brisbane Australia

[BillK]

Cant help you with the flow but we did a small block with the fast burn heads a few years back for a friend of mine and he ended up having to get custom headers made for a 67 Chevelle Something is different about the exhaust port location. He could not find a catalog header that would fit

[Zing]

Thanks ay
I will be building my own custom stepped 4into 1 merge collector pipes for the exhaust
Not much info on flow really?
Some info shows Max 230cfm some says 260cfm +
If they are only 230 at 5-600 lift stock I’ll go with the Ebay alloys?

[Elroy]

The exhaust port is raised but the bolt holes in the stock location. Takes some grinding and slotting etc to get a decent fit there.

In the right hands the fastburn can be pretty damn good. If you can buy them for the price of Chinese heads i would buy them regardless if you use them on this project.

[1980RS]

Hi, welcome to the site. I would take a set of Fast Burns any day over a set of feebay heads. My 062 Vortecs have performed beyond my expectations and the Fast Burn 200 cc runners would be even better on my 406 (after a little porting). Feebay heads? buy'em and use them for door stops.

[Zing]

Do the Gm Fast Burns require much work to support what I’m chasing?
I was hoping light bowl, short turn , runner inc pinch and some seat blending?
Or am I asking too much
Do the fast burns with some mild work support enough for 383ci at 6500rpm to make hopefully around 550hp with approx 250@50 approx 550 lift? Solid flat tappet
This engine is a budget build within reasons and wanted to stay with an ol school mech flat tappet
I’ve seen easy numbers with the Ebay Dart copy?
Do the fast burns have a weak exhaust port?
Does anyone have any relevant info on the fast burns on what work needs doing to the ports within reason to make them work. What holds them up if anything?
Realistically anything around 520hp if that’s achievable I’d be happy with
Thanks again

[1980RS]

Do the Gm Fast Burns require much work to support what I’m chasing?
I was hoping light bowl, short turn , runner inc pinch and some seat blending?
Or am I asking too much
Do the fast burns with some mild work support enough for 383ci at 6500rpm to make hopefully around 550hp with approx 250@50 approx 550 lift? Solid flat tappet
This engine is a budget build within reasons and wanted to stay with an ol school mech flat tappet
I’ve seen easy numbers with the Ebay Dart copy?
Do the fast burns have a weak exhaust port?
Does anyone have any relevant info on the fast burns on what work needs doing to the ports within reason to make them work. What holds them up if anything?
Realistically anything around 520hp if that’s achievable I’d be happy with
Thanks again

I don't think 520hp is out of the question with the right cam and intake with the Fast Burns. They won't need much work and perform a killer valve job on them and pick up and easy 20hp.

[Tom68]

Certainly lifted that exhaust port.

GM made 425@5400 with a dual plane, 770 Holley Vac (wonder if they fully opened ?) and a 222 230 112 hyd roller on a 383.

20220614_151846.jpg

[steve cowan]

G’day I I’m building a 6500rpm 383 Sbc chasing maybe around 550hp
I know very little about the GM Fast Burn cylinder heads, but I’ve been offered a set of new old stock cast number ends in 7712 for the same price virtually as a pair of Ebay 200 Dart Platinum Copy Kmj Assault style alloy heads.
Both with minor porting and seat work which would be a better option?
Not much info over here in Australia on the GM Fast Burn heads?
I know I can get the Ebay Alloys to work but what about the Gm Performance heads in comparison?
Thanks for any info
Matt Brisbane Australia

I don't have a link but if you search Engine 383 dyno results Randy made close to 700hp with those heads.
383 sbc 11.5:1 comp
From memory they are actually 200cc and flow 260ish
If it was me and you can do headers to suit,buy the fast burns.

[Zing]

Steve I’ve seen results ranging from 235-270cfm for the inlet?
How strong is the exhaust side? Ratio?
I’ve read in an instance, the inlet flow is the same as a Canadian cast L31 062 Vortec ?
Was hoping for some bowl n blend inc clean up runners and pinch inc seat work would be enough.
Wondering how much work is required to achieve around 280cfm@28 with the Gm heads
I know it’s easily achievable with the Ebay Dart copies, but for longevity and quality I’d assume the GM heads would be a better thing.
I build two stroke race engines & port two stroke cylinders for a living, I have all my own equipment for porting.
I was which ever head I chose going to get my friend in his machine shop to lightly cut some nice seat profiles, and I was going to do some light porting myself.
I’ve ported and done a few sets of normal style V8 heads, with before and after bench results but never touched these Vortec style port with a fast burn chamber.
I know I could improve on the Ebay Dart copy alloys, but I don’t want to ruin the Gm Fast burns?
I’ve been told they are a different kettle of fish?
I’ve got half an idea,been around benches and porting all different types of engines for 30yrs
If anyone has any pointers on where they need work to pick up enough to support my project?
I’ve got more than enough equipment to do the job just need some advice if I was to do the GM Fast Burn Heads
Cheers Matt

[skinny z]

I don't have a link but if you search Engine 383 dyno results Randy made close to 700hp with those heads.
383 sbc 11.5:1 comp
From memory they are actually 200cc and flow 260ish
If it was me and you can do headers to suit,buy the fast burns.

Thanks Steve.
I believe this is it.

viewtopic.php?t=34126

[Zing]

Steve and Skinny Z I’m wondering though, did Randy331 go to town and do a full max effort porting job on the Gm fast burns on that post?
I doubt they’d be anywhere near stock,knowing some of the heads he ports?
He must of used up a few of his tricks and time to achieve those results?
I’ve had people tell me they are stuff all better than an iron L31 062 Vortec?
I’m not chasing that much but I need to know what’s involved in achieving around 275-280cfm by 650lift?
Does anyone know any tricks to pick up a few cfm out the the Gm Fast Burns?

[skinny z]

Exactly which heads are we talking about?
I've seen "new old stock cast number ends in 7712"
Tom posted a picture out of GM's catalog that shows 12464298.
The link to Randy 331's thread described GM Fast Burn but states "GMPP fast burn heads with 2.02"/1.56" valves with a finished volume of 210cc. (were GMPP vortecs).

Stan Weiss' database may have info depending on what we're looking at.

http://users.erols.com/srweiss/tablehdc.htm

Stan Weiss.jpg

[Zing]

Yes I’ve seen that site Meaux racing showing mid 230@600
I’ve also read on here from the guys that do all the 604 circle track work engine that the castings can vary over 40cfm?
225-265cfm@600 he states he has flow sheets from over 200 pairs of these style of heads
My cast number is 0-12367712?
That is the bare head casting number, I think the number 12464298 is the same 7712 casting but as a loaded complete head.
I can’t work out how to attached a photo in my post?
I know the Gm quality is there but this is why I was thinking maybe the Ebay Dary copy?

[Zing]

Yes I’ve seen that site Meaux racing showing mid 230@600 which is pretty bad I thought
But then I’ve read people making over 500hp with them on 388, don’t know how much work though?
I’ve also read on here from the guys that do all the 604 circle track work engine that the castings can vary over 40cfm?
225-265cfm@600 he states he has flow sheets from over 200 pairs of these style of heads
My cast number is 0-12367712?
That is the bare head casting number, I think the number 12464298 is the same 7712 casting but as a loaded complete head.
I can’t work out how to attached a photo in my post?
I know the Gm quality is there but this is why I was thinking maybe the Ebay Dary copy?