302 casting swirl port heads

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65Vart

65Vart

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I may have asked you guys this in the past,but, I am thinking of picking up some 302 casting 318 heads (swirl ports) out of an 86 New yorker rather then getting my 273 heads re done. These have the right valve size so no need for notching the block. Questions are, will my push rods work or do I need a different length? do the rockers drop right on? will I need to do anything to the heads/block to keep the 10:5 or what ever it is at now?
Thanks in advance.
 
I was talking about pooshrods....... They sould be the same, only way to know if other things will work is to look, measure, and inspect........
 
The pushrods will be fine.As mentioned watch for the oddball intake bolt angle. Good plan swapping to the 302 heads. What sort of cam is in the 273?
 
Yes ,very aware of the intake situation, I have a rare Eddy D4B made for the 64/65 heads I might have to shelve. I am running a Comp cams .468 lift with 270 duration.
 
Check bore diameters 273 versus 318. I know valve shrouding can occur just not sure where. Maybe its 915 heads that conflict. Either way , better safe than sorry.
You can drill the stock intake holes with a hand drill ( others have ) . I think I would set the intake up in a drill press or milling machine to correct the hole angle. To do it by hand doesn't guarentee the bolts will all start straight and pull down correctly. The land angle under the bolt head is just as important as the hole.
 
So, not to hijack the thread and it is related to the topic (or at least the title of this thread.) :)

Is there a way to identify these heads if I were to go to a junk yard and try to get a pair? I assume that "302" is the casting number...if so is it actually stamped on the head somewhere? I know they came on 1986-90(?) 318s, but I'm so uneducated about this stuff I'm not sure if I could tell the difference between a 318 and a 360.
 
daginsu said:
So, not to hijack the thread and it is related to the topic (or at least the title of this thread.) :)

Is there a way to identify these heads if I were to go to a junk yard and try to get a pair? I assume that "302" is the casting number...if so is it actually stamped on the head somewhere? I know they came on 1986-90(?) 318s, but I'm so uneducated about this stuff I'm not sure if I could tell the difference between a 318 and a 360.
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The numbers are cast on the head, in the middle on the bottom under the head. The "302" numbers are the last 3 digits of the casting number.

360 heads are open chamber @ aropund 70 cc or greater, 318 heads are a bit smaller and that is easy to see when you have seen both, even more so side by side. You should get a book on this and copy the page of head I.D. numbers down for junkyard crawls.
 
RedFish said:
Check bore diameters 273 versus 318. I know valve shrouding can occur just not sure where. Maybe its 915 heads that conflict. Either way , better safe than sorry.
You can drill the stock intake holes with a hand drill ( others have ) . I think I would set the intake up in a drill press or milling machine to correct the hole angle. To do it by hand doesn't guarentee the bolts will all start straight and pull down correctly. The land angle under the bolt head is just as important as the hole.
Click to expand...
no valve shrouding I am told with the 302s, thats one reason I am considering them.
 
You may know that the 4233302 heads have smog pump holes under the exhaust ports to plug. I tapped them to 1/4-20 and threaded bolts in. You will be better off getting a length checker pushrod from Comp cams, ball/cup, and getting the proper length pushrods. 7.500 is a rough stock length, sometimes you need a little more. I used the stock 273 adjustable rockers on my 318 but I had to use shims available from Hughes engine to cente the rockers over the valve tip. All in all, it is a litlle bit of tinkering but the "302" heads work well with smaller bore engines.
 
They should attach with no issues. The chambers may be a little larger than the 273 head's chambers. Pushrods should be the same, but only really measuring will tell you for sure. Rockers will bolt right on.
 
The 273 pushrods work fine with a flat tappet cam. If you want roller lifters, use the '86 pushrods and the valley plate that holds the roller lifters.

Since you mention keeping a 10.5:1 compression ratio, I'm assuming a Commando engine that has adjustable rocker arms. If you're using solid lifters, use the 273 rocker arms, if using hydraulic, use the arms from the '86.

FWIW: I had no "smog" holes under the exhaust ports on my 302 heads in the Demon. If present, do per 66dartman.
 
2 Darts said:
The 273 pushrods work fine with a flat tappet cam. If you want roller lifters, use the '86 pushrods and the valley plate that holds the roller lifters.

Since you mention keeping a 10.5:1 compression ratio, I'm assuming a Commando engine that has adjustable rocker arms. If you're using solid lifters, use the 273 rocker arms, if using hydraulic, use the arms from the '86.

FWIW: I had no "smog" holes under the exhaust ports on my 302 heads in the Demon. If present, do per 66dartman.
Click to expand...

If it is a "Commando" engine, and still has those "pop up" domed pistons, I question whether there will be enough clearance with the 302 heads..

The little roller 318 I just put together had those 302 heads, and they are pretty closed.
 
HemiEd said:
If it is a "Commando" engine, and still has those "pop up" domed pistons, I question whether there will be enough clearance with the 302 heads..

The little roller 318 I just put together had those 302 heads, and they are pretty closed.
Click to expand...
looking at this old thread before thinking of purchasing these, Is there a clearence issue with the 10.5 :1 commando pistons? Never heard of this.
 
I'm glad you brought this up Vart. I had a pair and sold them. I have another pair found and planned to freshen them up. They should be a great replacement for the originals.
 
I wont insist there is a conflict because I haven't seen it with my own eyes.
I read somewhere that the edges of the valves sit outside the 273's 4.0 diameter bore so the top of the block would need to be notched.
I dont know if the commando pistons would create another conflict that cometic head gaskets for a 318 wouldn't cure.
 
RedFish said:
I wont insist there is a conflict because I haven't seen it with my own eyes.
I read somewhere that the edges of the valves sit outside the 273's 4.0 diameter bore so the top of the block would need to be notched.
I dont know if the commando pistons would create another conflict that cometic head gaskets for a 318 wouldn't cure.
Click to expand...
valves in the 302 casting (non HP )are the same size as the 273 . No notching needed.
 
RedFish said:
I wont insist there is a conflict because I haven't seen it with my own eyes.
I read somewhere that the edges of the valves sit outside the 273's 4.0 diameter bore so the top of the block would need to be notched.
I dont know if the commando pistons would create another conflict that cometic head gaskets for a 318 wouldn't cure.
Click to expand...

The problem with big heads on a 273 is that the bore size is small. (3.630).
If it were a 4'' bore the big valve heads would work. You can put 318 heads on a 273 but 340-360 heads will probably have clearance issues. tmm
 
65Vart said:
I may have asked you guys this in the past,but, I am thinking of picking up some 302 casting 318 heads (swirl ports) out of an 86 New yorker rather then getting my 273 heads re done. These have the right valve size so no need for notching the block. Questions are, will my push rods work or do I need a different length? do the rockers drop right on? will I need to do anything to the heads/block to keep the 10:5 or what ever it is at now?
Thanks in advance.
Click to expand...

Be sure to check the exhaust manifolds by mocking them up to the head. This is very important on the "64" - "66" A bodies since the Drivers side manifold may hit the port boss or the bolt ridge on later heads and not seal, or worse, crack the exhaust manifold. And as metioned above, plug the smog holes below flush beneath the exhaust port.
 
Going from closed chambered 273 heads to 318 '302' heads is like staying with the 273 head but spending more to do it. lol

They are the same port and both are closed chamber.

They flow the same numbers, and if the 302 has a swirl port...then all 318/273 are swirl port.lol
 
1wild&crazyguy said:
Going from closed chambered 273 heads to 318 '302' heads is like staying with the 273 head but spending more to do it. lol

They are the same port and both are closed chamber.

They flow the same numbers, and if the 302 has a swirl port...then all 318/273 are swirl port.lol
Click to expand...
"There is an interesting excerpt in "Mopar Engines", page 72, describing how such a head was ported and made to flow as well or better than other small block cylinder heads. Apparently, this experimentation resulted in the master for today's Mopar Performance P4452758 cylinder head". In othe words,these heads flow as good as any older stock 340 head.
 
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