302 swirl port heads on a 360

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63dartman

63dartman

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Are the 302 swirl ports a good option on a 360? I would probably have the larger valves installed and open the intake and exhaust to match my eddie performer rpm manifold and headers. I also have a set of open chamber j heads with 1.88 and 1.6 valves I can use. This is going on a stock bottom end rebuild.......not sure if it's worth the extra money to have the 302's worked on or not. The goal I am looking for is increased compression and hp.....any suggestions would help out alot.
 
'302 heads are a poor candidate for a 340 or 360, in fact, for performance purposes in general.

The better head would be a '308 head, but even it has small exhaust ports, though people with flow benches swear they can outflow 'X' or 'J' heads.

Mark.
 
thanks mark, I do plan on changing the cam right off the bat......is there any cam that will work well with a relatively stock bottom end and j-heads? I've tried to decifer cam specifics but I haven't done enough home work to understand the realtionship of duration, lobe lift, and seperation, and the other stuff. I've been going with the rpm range of the cam and total lift along with the little articles that tell you if it has lope or needs a stall and such.
 
302s work very well in 340/360 applications. The right ones. If hp is your goal, then it's not the right setup. They will make mad torque, and will be very strong up until about 5500. That's where my 360 gives up. Mine I ported to the larger intake size, but really didnt make the rest huge. It's enought o smoke the tires in 1st and 2nd in my Swinger, and pulls fine in OD with 3.55s at 1500rpm.
For your use, I'd suggest a set of factory Magnums. They have better ports, and the chambers are even smaller than 302s, in addition to having the larger valves. Basically bolt on too.
 
Watch if you do that and don't have a roller cam block, you'll need the special length pushrods and lifters with push rod oil provisions, available from ma Mopar (Jeep)
 
moper, that sounds exactly what I am after, I don't run over 5500 very often, well actually only once when my tranny downshifted at 70.....plus my bottom end is pretty much stock, I thought that anything over 5500 on a stock bottom would be gambling. Am I wrong here? As for the magnums, do you know the part number for them special pushrods? and thanks a bunch. I also ordered my cam from jegs today.....going with the voodoo Lift: .454''/.475''
Duration: 256°/262°
RPM Range: 1000-5500

got new comp cams springs too, I thought about it for awhile and for now I am just going to bolt the j-heads I have for now. (less money out of my pocket.) But I am going to be looking for the magnum heads for later.
 
Thanks Whitey, I haven't been down thw magnum head road yet, So you can bolt magnum heads on a non-magnum engine? You wouldn't happen to have those part numbers for the lifters and pushrods?
 
Magnums will bolt up to LA engines. You need hollow pushrods and lifters with oiling holes in them (AMC type). Im pretty sure 90% of the aftermarket mopar lifters are AMC type anyways. Youre best off measuring pushrod length and having them made by Comp Cams or Smith Bros. You will also need Magnum head bolts wich are about $25 from the dealer and either a Magnum intake or redrilled LA intake. You can use LA valve covers but they use less bolts then the Mags do.
 
And make sure you measure the pushrods and then measure them again. That way you can avoid wiping 2 cams the way I did.

Jack
 
For the hollow pushrods you can use the old style ford 302 boss oem's, exactly the right length for a non adjustable valve train, on the magnum head conversion.
 
Thanks for info on the magnums guys. If I use the ford pushrods do I have to give my engine any anti-rejection medication?
 
I remember getting the pushrods that mopar offers for this type of swap, it's in the 02 catalog I beleive in the LA Engine section, I checked the length and it was exactly what I needed. the heads were shaved slightly to true them up. But you can get everything from Ma Mopar. Yes you can use the LA valve covers, use the HD reuseable gaskets from Mopar and fill the unused holes with silicone. I happend to find an article in the Mopar magazine that usually sits on the parts counter at the dealer, and it was right from MPP about doing this type of swap, plus I have the article from Mopar Muscle on Magnum Head Swaps. Worked out sweet. I used the MPP 340 cam, 9.6 CR, internal balance and a Professional Products air gap intake and I'm going to use the Holley St Avenger 770 carb. Can't wait for my car to be done so I can try this out.
 
63dartman said:
Are the 302 swirl ports a good option on a 360? I would probably have the larger valves installed and open the intake and exhaust to match my eddie performer rpm manifold and headers. I also have a set of open chamber j heads with 1.88 and 1.6 valves I can use. This is going on a stock bottom end rebuild.......not sure if it's worth the extra money to have the 302's worked on or not. The goal I am looking for is increased compression and hp.....any suggestions would help out alot.
Click to expand...

If you are going to rebuild the bottom end I would suggest that you go with a piston with a higher compression height such as the Speed Pro CP116 or Keith Black KB107. One of these pistons will get you into the 9:1 compression range without decking the block or over 10:1 with a zero decked block with your J heads. Certainly will be a lot cheaper than working on the 302's.
 
dgc333 said:
If you are going to rebuild the bottom end I would suggest that you go with a piston with a higher compression height such as the Speed Pro CP116 or Keith Black KB107. One of these pistons will get you into the 9:1 compression range without decking the block or over 10:1 with a zero decked block with your J heads. Certainly will be a lot cheaper than working on the 302's.
Click to expand...


I missed that part, but Dave's right. Pistons will be $200 more give or take for ones that make decent sqeeze..The heads will need much more, and you're buying pistons anyway.
 
All this being said, why not just buy a 360 Magnum and get it over with?
Do a rebuild, stuff a slightly larger cam in, buy an A.M. intake for Magnum heads (or re-drill, your choice) and you're done.

I have a line on several rebuilder 360 Mags.

Mark.
 
O.K. guys here is the scoop, My engine is already rebuilt picked it up today. It has stock dish type pistons, I took your advice and bought the speed pro pistons @ 4.06 bore(engine block had to go 60 over) I talked to the people that rebuilt my engine and they say that if I change out the pistons I need to get my rotating assembly balanced again.

Is this true? they said it would vibrate "severly" I did not do my homework once again and it seems I may be paying for it. Also I need some help on how to push the pins out of the stock pistons and into the new pistons without damaging anything.


And lastly, If I do not need to rebalance the rotating assembly can I replace the pistons without unbolting the crank?
 
Listen to what Mrmoparech has to say. He knows his stuff. He will also tell you about BJRracing. He is another great source for info on what you have to do. They both do this for a living.

Jack
 
You don't have to swap the pistons to use Magnum heads.
I certainly wouldn't use KB garbage, run forged.
Magnum heads bump the compression up slightly over the 'J' heads.

In truth, there is nothing wrong with your originl set-up combined with a set of conventional 360/340 heads.

Mark.
 
Mark Nixon said:
You don't have to swap the pistons to use Magnum heads.
I certainly wouldn't use KB garbage, run forged.
Magnum heads bump the compression up slightly over the 'J' heads.
Click to expand...

And what's wrong with Keith Black Hypereutectics?

Hypereutectics in general are much much stronger than a standard cast piston at a small increase in price. They are also much more thermally stable than either a cast or forged piston allowing them to be set up with much tighter tolerances which improves the efficiency of the engine and longevity of the rings. For a street or mild street/strip motor they are an excellent choice.

When I built my 360 the machine shop made a comment about the KB107's I was using. The accuracy of the machining and the consistency of the weight made the high end forged Probe and JE pistons he was fitting into other engines look pretty bad.
 
#302 heads on a 360 work great on the street. I've got a bone stock set on top of a very mild 360 (MP RV cam is the only mod) with a 850 TQ and the bottom end is crazy. However it's not your best choice if you want to rev.

This is in a 4000 lb Diplomat, 2.94 SG rear, A904 trans, 245 tires. .024" thick head gasket and 57cc chambers IIRC....8.9:1 CR, runs on 91 octane. It can get 20 US mpg hwy.
 
Hey RANK,

Sounds just like the setup I am putting together. I've got a 1980 Volare Coupe that I have a comp cams xe262,stock bottom end and "596" heads with 1.88 intake valves. Its got a 727 with a 7.25 sure grip. I was attempting to duplicate the Mopar Muscle Magazine article in which the were able to obtain 335hp with my setup using an unported Edelbrock Performer intake,comp cams xe262,stock rebuilt 40 over bottom end and a TQ carb.
The article can be viewed at http://www.compcams.com/Community/Articles/Details.asp?ID=-409383413

Has anyone ran quick on this type of setup?

Great forum.
 
Hey Rank and Bongy, thanks for the posts and the link to that low comperession 360 build-up, I'm starting to think that there is hope for my "lowly 360" build. I have decided to not mess with the stock pistons and leave as is. I have another 360 block I can build at a later date with the speed pro pistons if I choose.
 
IMO (again) if you're going to mess with '302 castings, pitch them and run Magnum heads.
They really aren't that expensive and the gains far outweigh that of the ease of installation on the '302s.

FWIW, I get 318 Magnum heads for under $50 a pair.

Mark.
 
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