[Bull_81073]

Ok so I have a 327 SBC that I purchased off of craigslist from a guy who pulled it from his project truck in favor of a rebuild. I dropped it into my circle track stock car after I toasted the bearing in my 283. I did this last year and am looking how to increase it's performance as I am already running near the front but would (Always) like a little more. So I looked at the heads on this motor and they are number 8973487. I can't find this number on mortec and I want to know the cc's on it. The heads on my 283 are a 60cc set that were checked by my machine shop and were given new springs etc.

So I basically want to know before I take those off of my 327 what do I have now and can I increase my HP by swapping.

 

[DoubleVision]

3973487....71-72...350..........1.94/1.5 or 2.02/1.6 valves, was also used on '71 350/330hp LT1
These are large smog chambered 76cc heads. Unless domed pistons were installed in the 327 then the compression is likely around the 7.5:1 range, not good. However, they do have 160cc intake ports and the open chamber unshrouds the valves. the large chamber on these heads is not efficient.
Are these heads better than the heads on your 283? give us the casting numbers and we can tell you. Most heads that came on 283`s were small valve small port jobs to keep velocity high in a small cubic inch engine.

 

[Houston54]

The 487 heads are some of the better stock iron heads. They are sought after by stock class racers because of this. While they are not in the same class as vortec or most aluminum heads they are not terrible.

I have a set of these on my current 350 and have an extra pair in stock along with a pair of the 487X heads which have the larger valves.

 

[Bull_81073]

Ok, I am not in the same city as my 283 right now but the heads that are on it are no the ones that came with it. I purchased them from another guy who had them as spares. I looked through my notes and I think that they are a 376450 but I am not 100% certain. I do recall that they are a 60cc chamber but don't seem to have the casting # for certain. I'll call down to my brother in law and see if he can double check for me.

 

[DoubleVision]

If they are 450 castings that`s even worse, the ports on these heads are tiny as are the valve sizes.
376450.....75-81...262/267/305..6 or 7 exhaust bolt holes, 60cc chamber

 

[Bull_81073]

The 487 heads are some of the better stock iron heads. They are sought after by stock class racers because of this. While they are not in the same class as vortec or most aluminum heads they are not terrible.

I have a set of these on my current 350 and have an extra pair in stock along with a pair of the 487X heads which have the larger valves.

When you say that stock classer like them I don't know if you really mean me though :thumbup: Our class is very restricted and I have to pull 15" of vacuum. As I said before I am running a 327 so if these heads have 76cc smogger chambers on them then I won't get what I am looking for from them. Reguardess of the efficiency of the runners. Right now I have a 3.83 rear gear and run in second with my TH 350. I'm pulling right around 5300 Rs at the end of the straight but I think I might be leaving some on the table.

I guess the real question is when I am certain of the number of my heads on the 283 will they increase my HP. I know they'll bring up the compression if the 487 s are a 76cc chamber but I don't want to starve the motor for air at the top end either. I'll get back to you with the number ASAP.