What is the difference between 396 truck heads and regular 396 heads?Is it ok to use truck heads instead of regular heads?

What is the casting number on the heads?

What is the casting number on the heads?
3975950

3975950

3975950....68-70...oval...OPEN...396, 402 Truck, 366T, 427T
very poor casting for performance. Small ports, head is for low-end torque.

Are the intake ports wider than they are tall??

I ask b/c they are lo-po, peanut port heads!!

Otherwise, if the ports are taller than wide, they should be fine b/c they will be regular large ovals..

pdq67

I have to say that I am running these heads on my 402 and I have srceaming performance, especially mid to upper rpms (2,500-6,000). I put a 2006 Dodge Viper to a test last week. They are 109 cc and not peanut ports.

At least some, if not all, of the early "TRUCK" heads have the large oval intake port openings NOT peanut ports. The actual port volume may be different (may be smaller further into the port) but I've yet to take a measurement on that.

Rod

I am going to be some "fine tuning" this winter on my motor and the heads were my first thought. Is anyone else running these 950 heads and what kind of work have you had done? Thanks

Guy's,

I have found out after MUCH looking and guys commenting about this BUT NOBODY having any head numbers to back it up, that there are BB TRUCK heads that have 1.84" and 1.94"/1.66" valves in them that are true large oval heads!!

All you have to do is ream them out such that you can install either 2.06"/1.72" or 2.19"/1.88" valves in them and you are good to go!!

Check the Canada engine part supplier "amotion's" site out for info on this...

http://www.amotion.com/

pdq67

3975950Do you have the heads off the car? Do you have access to a digital camera to post a pic for reference of the casting number, the chamber, the ports? Maybe we can start an archive of this stuff.

Rod

There seems to be a bit of confusion about these heads and since it seens like there are a few of us with them, what is the truth??? I have reviewed several different sites from Mortec to some Chevy web sites and it seems like they all have a different opinion about these heads, especially if they are open or closed chambers. All I want is the truth....." You can't handle the truth"...yes we can.....

There seems to be a bit of confusion about these heads and since it seens like there are a few of us with them, what is the truth??? I have reviewed several different sites from Mortec to some Chevy web sites and it seems like they all have a different opinion about these heads, especially if they are open or closed chambers. All I want is the truth....." You can't handle the truth"...yes we can.....
I think if we started archiving pics that would help.

despite confusion, these heads seem to be TRUCK heads. and truck motors are designed for what? torque in the low rpm's and midrange. large intake runner volume/ valves would only hurt the trucks ability to produce low to midrange power. therefore heads such as these should provide some nice low end throttle response and pretty good midrange, but will not flow well to produce a lot HP on the big end.
now frank's story seems to conteract this, having big upper end power. vipers were 500 horsepower a few years back, i gotta think they are over that now. how close was that 'test' frank?

Fwiw, my '75 454 P/U motor had -781's on it!!

As well as true, stock bore single-notch flat-top cast pistons! Talk about it's CR. sucking!!

pdq67

GS-
When I do get on it my optimal shift point is near 5,700-5,900....and it's not flattening out by any means either.
I'm running 3:31 and was on a slight roll when we ran. It was close until we hit 3 digits and I decided that it was not safe nor did I have much chance trying to keep up with him after that. So now does that confuse everyone more about these 950's having no top end????

yes, it is very confusing. i have a 433 inch BB, pro-topline alum heads with 320 runners, 2.25/ 1.88" valves, high compression, nice cam, 4 speed, 3.31's and i don't think there is any way i could hang with a new viper. sure a chevelle probably weighs about what a viper would, but the viper has the advantages of being fuel injected, more aerodynamic, most likely lower geared with it's OD trans, etc...
you'd have to be making over 500 horsepower with these 950 heads to stay with a viper up to 100mph. a new Z06 corvette is 500HP and runs low 12's. the viper is undoubtedly faster being a v10 and costing $30K more.

GS- Could he have been toying with me ??? Don't know. All I know is that I'm still pulling at 5,700 rpm's which brings us back to the 950's only being bottom to mid range rpms. This fall I will be pulling them off and taking them to a head shop to verify valve size and if there has been any port work done.

i'm thinkin' he must have been or he didn't know how to drive it. that doesn't mean you don't have a stout running car, but you better bring something really special to outrun a new $90,000 sports car.
possibly your heads have been majorly ported and outfitted with larger valves? pulling strong to 5700 is very impressive with small valve heads. that's about where the L78's and LS6's would build max HP. what's the rest of your combo?

Unfortunately, I have no clue what is under those heads but from everyone that has ridden it it we all agree it was definately balanced and blueprinted. Just for the heck of it, we used to get that thing into the low 6,000's but then it starts to fall off. I don't go that high anymore but I know it can take it. When I get it apart this winter we will all know what its got. It sounds like you have almost the same setup as me. Have you ever run that in the 1/4? As soon as I get a new clutch in there I will get it on a dyno and post results.

no, never been to the track. i only have 250 miles on this whole car since restoration, so i'm still working out problems. at this altitude we all run about full second slower than at sea level. i'm thinking i could run mid to upper 12's at sea level.

Viper!!

Yes, bring something called BIG POWER!! I'd start with at least 550hp!!

pdq67

Just to bring this topic back up, I was doing some searching trying to figure out some info about these heads myself because I run them on my 454. As far as performance numbers, I had these heads on a .030 over 454 with 11:1 closed chambered pistons, a .550 lift hyd cam, torker II intake and 750 dp. The car had 3.55 gears and a 2600 stall converter and ran 11.80's with these heads bone stock (full weight 68 nova). I have since gasket matched them put 4.10's in and went to a .600 lift cam and I have to say I know the car is way faster then before though I have no numbers yet to back this claim. By the way these heads are NOT peanut port heads.

Just goes to show there are lots of GM castings, that are not the 'popular' ones we all know about, that can be made to work really well. Good luck, let us know the new numbers when you get to the track! (In a few months, seeing as you're in Ohio)

Per Ed Staffel's book.

-950 heads are SMOG large ovals that have the chambers squared off over by the exhaust valve so that they hardly have any quench.

Truck use castings and can have anywhere from 112 to 124 cc sized chambers so you really need to cc them.

And years and years ago onna the mag's did a rebuild of them just b/c they had them and they did quite well in a rebuilt hi-po application!!

I have the old mag somewhere. Seem's they were on a Monte....

I'd use them...

pdq67

I have the old mag somewhere.

Paul, look in the magazine rack next to the toilet:p :p

He, He!!

It's in onna the many boxes in my bedroom closet is where it's at...

No room for clothes, just mags and new engine parts!!!!

pdq67