[speedfreek]

I have a couple of 454 heads that I was looking at and noticed something kinda weird.
One head list as:75-87 oval, open 120cc 225/116 ports (maybe car) says "PASS"
Other head lists as: 68-84 oval open says "TRUCK"

The one that says truck, the intake runners are way bigger than the pass ones. Would this mean that the "truck" heads would give more horsepower than the pass ones?

[dubs68camaro]

Just taking a stab at this.....I'm wondering if someone had done some port work on the "truck" heads. They are more than likely both 2.06/1.72 valved heads, so I doubt there would be a difference if any in the runner cc size. Let's see what the "others" have to say.

Actually, now that I think about it, the other one is probably the 255 intake port (I think it's still the same valve size though). I'm not sure if 25-30 cc would be that noticeable though. I'm still thinking port work maybe.

[speedfreek]

Originally Posted by dubs68camaro

Just taking a stab at this.....I'm wondering if someone had done some port work on the "truck" heads. They are more than likely both 2.06/1.72 valved heads, so I doubt there would be a difference if any in the runner cc size. Let's see what the "others" have to say.

Actually, now that I think about it, the other one is probably the 255 intake port (I think it's still the same valve size though). I'm not sure if 25-30 cc would be that noticeable though. I'm still thinking port work maybe.

I looked for possible porting but it doesn't look like anyone touched them.
It's kinda weird, I have read about "peanut ports" and "large ports" but the "peanut" are on the "pass'' heads? I'll go measure the truck valves but I can't measure the pass ones cause their on the motor.

[speedfreek]

Just tried to measure the valves. The intake measure 1.8'' and the exhaust is around 1.7'', couldnt get mic around ex valve. They look very small.
The runners are the same width(1.7'') but the trucks measure 2'' tall where the pass measures 1.7'' tall.
Which ones are better heads?

[dubs68camaro]

Originally Posted by speedfreek

Just tried to measure the valves. The intake measure 1.8'' and the exhaust is around 1.7'', couldnt get mic around ex valve. They look very small.
The runners are the same width(1.7'') but the trucks measure 2'' tall where the pass measures 1.7'' tall.
Which ones are better heads?

I will have to let someone else jump in on this one. I didn't know they made an intake valve as small as 1.8 on BBC heads. I just measured my 781's and they are 2" tall (2.06/1.72 valves)....I'm sure that would have to be the better head.

After checking Mortec, it does sound like those are the "peanut" round port which is why they are 1.7" tall instead of 2". There must be a lot of space between the intake and exhaust valve. Sell those to your neighbor as some rare racing head!!!!! LOL

[pdq67]

Fwiw, large oval BB heads whose intake ports are taller than wide, come w/ 1.84"/1.94" and 2.06" intake valves and 1.66" and 1.72" exhaust valves w/ the 2.06"/1.72" MOSTLY on cars and them and the smaller valved on TRUCKS!!

Peanut port heads ports are wider than they are tall and if stock can go from say 200 to maybe 230 cc's(??)

Now the newer L-29 BB Truck head that replaced the peanut port head has smallish real large oval ports that are right at 230 or so cc's, a 100 cc fast-burn heart-shaped open chamber and good, although small, exhaust ports!!

I'd either hunt up a set of early closed chambered heads like the old -206's or semi-closed like the -215's for flat-top pistoned engine use or regular large ovals like the -781's and -049's open chambered w/ low domed piston engine use!!

Take your pick!

pdq67

[dubs68camaro]

Originally Posted by pdq67

I'd either hunt up a set of early closed chambered heads like the old -206's or semi-closed like the -215's for flat-top pistoned engine use or regular large ovals like the -781's and -049's open chambered w/ low domed piston engine use!!

Take your pick!

pdq67

I have a 460 with forged flat-tops. I took off the 781's and put on some 702 closed chambered ('65-'65). I'm around 9.5 or so and it really pepped-up the motor. No pinging at all. FWIW