304 rockers in 360 heads?

PaintedRat

I just tore down the 360 out of my Jeep to rebuild to run on propane. I believe it is a mid to late 70's motor, but I haven't pulled the casting number on the block or heads yet to verify. It has dogleg ports, bridged rockers, and two sizes of exhaust manifold bolts. I'm sending off the block to be checked and machined, and I've got a few weeks to focus on the rest while I wait. I tore apart a 304 recently to get it out of the garage, and the heads on it were very recently rebuilt. I kept the stamped rockers, bridges, pivots, and pushrods. The 360 had bridges with built on pivots. The parts on the 360 heads are all very worn and in need of replacement. Are the above parts interchangable for the 304 and 360? I would like to use the almost new parts and put that money to use elsewhere. Any suggestions? I will be putting in new valves and springs. I'm not expecting to go to roller rockers if that was a forthcoming suggestion.

jeepsr4ever

Yes they are interchangable. Do not use the cast aluminum bridges if you can get away with it. They are a one piece bridge and pivot that are prone to twist and do break often.

PaintedRat

Good news and great help, what could be better? Bottom end parts go to the machine shop tomorrow. After vacation next week, I can get to work on the rest.

PaintedRat

I didn't want to litter with another thread, so I'll just add here. I got a call back from the machine shop on the block. They can't smooth it at .040, so it needs .060. I'm planning this for a mostly trail rig, running propane as stated above. It won't be unheard of to be running for 8 hours, in temperatures into the 90's. With block filler, is heat going to be a problem? Am I going to have to get a new block, or do you guys think I can reliably work with this? I don't want to put all my money into a rebuild then have to start over.

Goose

My 360 is .060 over and has been for 12 years of heavy towing and off road use.. no heating problems or any other problems..and I havent filled the block or anything.

jeepsr4ever

You should have it sonic checked up and down all the bores in 5 locations per bore.

PaintedRat

I'll call the machine shop and see what they say about ability and cost to sonic check. What is a reasonable price to sonic check?

jeepsr4ever

$50-100

PaintedRat

The finish hone for my 40 over 343 pistons was enough to clean up the bores without going to 60 over. The machine shop said they expect to have parts ready for me to pickup on Friday. This weekend, I plan to start assembly, and paint the block. LQ phone cam pics forthcoming.

Any suggestions on the heads? (Comp Cams recommended a XE256H cam too)

I asked the shop about work to rebuild the heads. I'm having hardened valve seats installed, and they recommended harder valves as well. Standard valve sizes. I also need a bolt hole fixed. I'm looking close to $800 to finish them off figuring HD springs, and tax of $50.

$150 Magnaflux, valve job and surfacing
$160 Labor for seats
$135 Material for seats
$156 Valves (book listed for LPG applications)

My alternative so far is ordering a set of AeroHead Racing reconditioned heads for $679 with hard seats, and larger valves. Add shipping, and a set of hardened push rods, I'm right around the same price.

"These heads have outstanding features that include premium one-piece, stainless stell, high flow valves, heat treated and machined steal retainers and valve locks, seals, bronze wall valve guides, 3 angle valve job, and heavy duty valve springs."

"Select 344/502 Cast Iron Castings, 2.08X1.74 Stainless Valves, 58cc Chambers, .550‚Äù Lift Springs, and 3/8 Studs & 5/16 guide plates come standard. "

ironman_gq

you don't really want heavy valve springs unless you need them. they put too much pressure on the cam lobes and lifters and you have a better chance of wiping out a lobe on your cam. the heavy springs are only needed with high RPM engines to control valve float and keep them from hitting a piston.