Advice on which heads to use. 360 , 302???

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moparracer95

moparracer95

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Ok, I am in the final stages of putting my motor together and I have run into a fork in the road. I have a 318 std bore - Lunati cam .480/.480 and I can either run my 302 heads I was planning on running, or my buddy has a set of ported 360 heads assembled with comp springs for 100.00. I have a set of 273 Hipo heads that came off a motor with a crower .521/.528 cam and I was going to pull the springs off those heads and put them in my 302's. But I know the 302s run a rotator and I dont think the 273 did. Can I ever use these on 1990 302 heads?? If not I guess I will just buy the 360's. (360's have a stud that needs fixed, buddy couldnt get headders to seal on it) So I can live with that.. Just getting eager to get this back in the car, and dont want inpatience to mess my engine up.. I was thinking that with that size cam, Maybe I should go with the 360's due to the larger valves and ports.. Any advice or suggestions would be appreciated.. Thanks Matt
 
The 360 heads will drastically lower your compression ratio if their the older LA type heads. That's not a huge cam so I think the 302's are the way to go. Ports are a little smaller so they will make alot more torque and they have much smaller chambers so they'll make alot more compression. I believe the springs, retainers, and locks should all fit from the 273 heads onto the 302 heads as long as the valve stem diameter is the same and I don't think they changed it. Only problem you might run into is if the springs are dual springs you'll need to have your 302 heads machined to accept them. In stock configuration they only accept single springs properly. Even if they need machined I'd run the 302 heads. The big ports and chambers on the 360 heads will hurt your torque a bunch.
 
Yeah, they are older 360 heads.. Open chamber... My motor is a 1990 318 truck motor.. Just put cam in today and replaced lifters, timing chain. I am not really sure you would call the springs dbl. They have a single "round" spring with a "flat" spring coiled inside.. They look just like the ones on the 360 heads actually... Just trying to get this together with minimal more cash out.. (employment ended in April) and just using my time to get parts I have assembled.. Just need to figure out the heads and then intake.. I have a stock cast 4bl. but seeing as I have a Holley carb, I would have to use an adapter.. Not sure of those things, but cheaper than an air-gap!!! Maybe I will just take the cam back out and install the stock roller cam and lifters for now... Just had to install the fuel pump ecentric,(SPELLING???).. so I thought I would change cam out.. Hate having new parts sitting on the shelf unused... haha
 
You definitely don't want to use 360 heads on your 90 318. You'll only have about 7-1/2 to 8 to 1 compression. Those are just single springs with a damper. Not the same as dual springs. They should work fine so that's some good news. I know what it's like surviving these days and having to save a buck. Not buying the heads should help. The carb adapters work ok but not the best. Better off either getting a ThermoQuad or different intake. I see LD4B's advertised every once in awhile for $100. That's a good intake. Why are you thinking about swapping back to the original cam? I know a roller is good but the stock cam isn't much for performance. Although you can have it reground.
 
Thanks for the link... I was just paging through the classified myself haha... I was just saying that if I switched back to the roller set up I could just use the heads and springs (302) That I already have on the motor.. Although I am going to have to pull them back off to get the springs changed. But at least I should be able to reuse the head gaskets.. Just put them on a few days ago and well, seeing as the motor is still on a stand with no intake, it hasnt been run... Well, I am relieved that I can use those springs with no machining. I am new to this mopar engine building.. But I have a second motor already to be assembled to.. That is what is left of the motor I pulled the springs out of.. That was a stock 1978 318 bottom end with 65 273 hipo ported heads and 4bl intake, with the .521/.528 crower cam. This was one strange motor I found. I would of never thought a cam that size would run on a motor built like that.. But I guess it ran so all the pieces worked together.
 
Fishy is on it!

Run the 302's, you will be lucky to have 7.5-1 with the 360 heads, low comp, and big ports, would make it sound like it had a vacuum leak, and run like a sloth down low.

Sounds like you've got the plan. Enjoy!
 
Yeah, I guess I will stick with the 302's and replace the springs.. Thats the way I was going in the first place, when my buddy mentioned his heads.. I tried telling him that I though they would be overkill, but he said with the 480 cam, 3.91 sg , and my 3000-3500 stall, it would be ok. I just hope that cam is not going to be too much.. But I guess we will wait and see.. Thanks to all with the advice and Hopefully by this weekend, I will be ready to install it into the car... Then its on to mounting my shifter and getting everything wired...!!!! can hardly wait!!!! Thanks again.. Matt
 
That cam is a bit big for stock 302's but if you do some mild porting in the future they will complement each other very well. As far as intakes go you could find a used Edelbrock Performer for less than $80 and either bolt on the Holley that you have or get a ThermoQuad, rebuild it, then use that. If it's set up right and working properly the TQ will give you much better gas mileage than a Holley.
 
Yeah I am thinking about heading to the junk yard here in the next few days.. I need to find a deep water pump pulley too.. Ill look into that... Thanks for all your suggestions and I am sure I will have a great running dart by the end of this...
 
One last thing. You don't have to pull the heads to swap valve springs. You can buy a valve spring compressor and air hose attachment to inject air into the cylinder to hold the valves in place then use the spring tool to take them apart and swap them out. I even made my own valve spring tool with just some scrap metal I had. It's not the prettiest thing but works real good. It bolts down where the rocker shaft bolts down so it's easy to use. Here's a couple pictures
 
Ah I double checked the stall on my converter and it is a 2800 - 3200 Boss Hog. I thought it was steeper than that.. But you think the 360's would work??? Now I am getting confused.... I guess if the stall doesnt hit till around 3000, that might be enough flow... This is the whole dilemma that I was started with.... ahhhhhh.. I guess I could just try them both and see what is better??? I am sure my buddy would let me use them and see how they work... I mean , its really only another set of head gaskets.... not too bad...
 
I have a valve spring compressor.. But I lack the air.. My compressor died about two months ago.. Unless you think a pancake compressor will keep up.. I guess I can give that one a shot... ??? But I guess I could try the 360's and in the meantime, take the 302's off and gasket matched and springs installed.. I have one buddy that says I should run the 302's and my other buddy that has the 360's says I should run those... But his motor was built a little more than mine is.... But I guess I should start a poll and see what people say about the heads... I take everybodys points, but everyone seems to have valid points and me being new to the mopar engine build, doesnt know which way to go.... But I thank you all and hope to continue to recieve more and more info that would help me on this motor..
 
If it was me, I'd run the 302s with the springs, retainers and locks (and shims if there were any) from the 273 heads and sell the 360 heads. The 360 heads will be too much for the majority of the driving you are doing and tere's not enough compression to make them work well.
 
Yeah Moper.. Thats what I was leaning towards.. And yes there were shims.. So I guess I can gasket match the 302's for now and just let the 360 heads go.. I havent really bought the 3600 heads yet.. My buddy was just going to let me use them and see how I liked them.. But being open chamber, I was thinking it would be too much for the motor combo I have.. Thanks to all... But I guess I have made a decision to run with what I already have and not buy anything else for the time being... Thanks again to all who have chimed in with advice and I will post when it is completely installed and running!!!!!
 
moparracer95 said:
I have a valve spring compressor.. But I lack the air.. My compressor died about two months ago.. Unless you think a pancake compressor will keep up.. I guess I can give that one a shot... ??? But I guess I could try the 360's and in the meantime, take the 302's off and gasket matched and springs installed.. I have one buddy that says I should run the 302's and my other buddy that has the 360's says I should run those... But his motor was built a little more than mine is.... But I guess I should start a poll and see what people say about the heads... I take everybodys points, but everyone seems to have valid points and me being new to the mopar engine build, doesnt know which way to go.... But I thank you all and hope to continue to recieve more and more info that would help me on this motor..
Click to expand...

I have a friend that likes the heart shaped chambers in those 302 heads so much, he's going to mimic them on his slant six head by welding up the chambers and machining them in. But if you have enough old K car turbos laying around you plan on putting on that motor to justify running a super low static compression, go ahead and put on the big chambered heads.

An easy way to remove valve springs without air is to get some braided rope (like lawnmower pull rope or a little bigger), and then with the piston down the bore from TDC a little ways, feed it into the spark plug hole until you can't feed any more. You then turn the crank until the piston comes up against the rope enough to lock the engine up. At that point there is just about no way the valve going to go anywhere, and it becomes very easy to compress the spring and remove the keeper. And yes, I did learn this trick from a guy that repaired small engines for his living.

That said, unless the your piston rings are shot or one of the valves in that cylinder is so bad (bent, burnt, warped, or just worn away) air leaks past it, any small compressor can fill the cylinder with enough air pressure to do the job (and hand holding the air line just won't cut it, make sure you have the fitting that screws into the spark plug hole). If you do use compressed air to hold the valves shut, one thing to remember (wanna know how I learned this one) is if the valve moves off the seat for any reason, the valve falls into the cylinder. I had some keepers varnished to the stems once and while prying or banging them loose, you guessed it, lost a valve down into the cylinder. Nothing to do at that point but pull the cylinder head.
 
302's are your most economical choice for not killing compression. Bolt right on. So do Magnums,but they require more specific magnum only parts. Bigger ports than the 302.
 
302 head by far , if you have a die grinder slight rub on the push rod pleat that works well .
 
Thanks dart 76. You know who was going to sell me his old 360 heads.. telling me to run those.. But I have already started on the 302's so theres no real going back now as long as I dont need to get the guides machined for my cam lift.
 
Backyard mechanics solution to not having an air compressor to close valves. Get a length of cloth clothes line. Shove a bunch in through the spark plug hole with the piston at BDC leave some hanging out, rotate the engine around until the piston in that cylinder locks because of the interference with the clothes line. Remove valve springs and replace them. The clothes line will keep the valves from opening. Back off crank and pull the clothes line out. Move to the next cylinder.
 
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