Picked up a 1975 454 truck engine today and need advise on the heads. Casting # 346236. My research shows these are oval port 120cc open chamber , 225/116 ports (is this the valve size?).One site even said these are peanut ports I dont think these are good for preformance engines are they. My ques. is can these heads support 500hp w/ some work or am I wasting my time on them? It will be mostly sreet driven.
Thanks, Mitch.

Anyone? :confused:

I put a reply on my post Mitch, see if that gives you any info.

Originally posted by hamrdown:
Picked up a 1975 454 truck engine today and need advise on the heads. Casting # 346236. My ques. is can these heads support 500hp w/ some work or am I wasting my time on them? It will be mostly sreet driven.
Thanks, Mitch. I believe these are peanut port heads but I'll have to double check. Is the intake manifold off the motor? If so, is there anyway you can take a pic of the ports and post it for us? That way we can tell you definitely.

Peanut port heads were made for lower rpm, strictly torque motors. Speaking in GENERAL terms I would say that if they are peanut port heads you are going to want to look for different heads for your 500 hp motor. Which ones to look for... you say? It depends on the rest of the combo, like whether you are going to run flat top or domed pistons, etc., etc..

Rod

Alot of people shy away from peanut port heads,but if you are looking for a good running street big block designed for torque,peanut ports will fit the bill.Just because there peanut port doesn't mean that it won't run.My uncle has a 1970 nova,454 truck block,speed pro hyper pistons H581p,xe274h,performer rpm,carb is 800 quad,turbo 350,4.11 gears,275/60/15 BFG drag radial has run a best of 12.26@114 not bad for peanut ports.

Now, that's probably 102-105 mph in a Chevelle. Not bad. I'd run a single pattern cam for sure.

Originally posted by JRS70LS5:
My uncle has a 1970 nova,454 truck block,speed pro hyper pistons H581p,xe274h,performer rpm,carb is 800 quad,turbo 350,4.11 gears,275/60/15 BFG drag radial has run a best of 12.26@114 not bad for peanut ports. JRS70LS5, :cool: , I've been waiting for someone to give us the lowdown on a quick peanut port headed combo. Can you find out the casting number for the heads on your uncle's motor for me? I'm VERY interested to know! Thanks. I believe the 114 mph indicates high 11's! Whoa!

hamrdown, I checked and the casting number you have is for peanut port heads.

Rod

So if I did a little port and polish and maybe bigger valve's(?) these would be a good head for my 496 build , or should they be left alone? I'm lookin' for a torque monster to move my 73 Chevelle , but also need to save weight ,aluminum heads would be nice.
JRS70LS5,
If you talk to your uncle find out what mods he did to his heads. graemlins/thumbsup.gif
Thanks , Mitch.

Mitch; for a 496,I'd look elsewhere.As for spending the money for bigger valves,they'll yield nothing.If you're talking strictly torque,keep the stock valves,and do a quick bowl port.If you're looking for 500 ponies,get a set of large ovals.A few of the numbers to look for are 3856206,3872702,3904390,3909802,3917215,3931063,an d 3964290. Steve

If the ports are wider then they are tall, they are peanut ports..

Large ovals are the same width, but taller then they are wide.

And of course, rect. ports are just that, great big rect. shaped with small rounded corners! They are almost too big for any but the most hardcore streetrod guy's!!

Most of newer PP heads are down around 200 cc's or so, so the ones at 225 or so cc's are fairly big for PP heads b/c generally, large ovals start around 235 cc's or so..

And it has been documented that some of the BB truck heads have at times had both 1.84" and 1.94" intake valves in them along with 1.60", (or maybe 1.66"), exhaust valves so if you run across them, pass them up unless you want to really work them over.. But all in all, even they would be OK if worked over on a mild 396 work truck motor, imho...

pdq67

Originally posted by 67chevy2:
A few of the numbers to look for are 3856206,3872702,3904390,3909802,3917215,3931063,an d 3964290. Steve Don't forget about the 049's, from what I've read on this site, they are also one of the best oval port iron GM heads.

Thanks for the info. guy's. Been looking on ebay and it seem's that you cant give these head's away. Maybe I'll stick w/ my original plan and go aluminum to save weight. In the near future I'll be asking for advise on my 496 build up!!
Thanks , Mitch.