302 Engine Guru's help me please.

[5LugFoxFanatic]

I have an 86 Mustang that is pulling 70 psi per cylinder so I am thinking of rebuilding it for a few reasons. One to get rid of the flat top pistons so I can ad an aftermarket camshaft, and two to freshen it up. My engine has 136,000 on it and it smokes out of the tail pipes at WOT, so I am thinking the rings are bad. I came across a 1972 302 that has been worked over to it’s stock condition. The guy that is selling it said he replaced the following….

Honed the block, new lifters, new rings, new timing chain, new oil pump, new main bearings, new rod bearings, new cam bearings, new freeze plugs. It has the stock pistons, crank, and rods, and I am buying the shortblock and bolting up my e7’s and all of the accessories to it. Will all of my stuff bolt up to this block? I am not sure if there was a change in blocks where the accessories are mounted to.

Here are the concerns I have. This motor has a 28 oz flywheel and crank, and I’m pretty sure my 5.0 has 50 oz’s parts. Will this work with my car? Is there strength or longevity issues? He was telling me that 347’s sometimes come with 28 oz flywheels for some reason. Also it has a hydraulic flat tappet cam in it. I am sure my car has a roller cam. Is there a big difference that will affect anything? What do you engine pros think of the motor that I could potentially put into my 86? Worth it for 200 bucks? It has 0 miles on the rebuild because he wants to go with a 347 and twin turbos. I talked with him on the phone and he seems like he knows his stuff, but he told me to come out and look it over and that he wants to make sure it will work in my car before he sells it to me.

 

[joncash]

Here goes:
-The old 302 firing order will not match the firing order of your newer 5.0 H.O.. You can partially correct this by rearranging the spark plug wires on the
distributor, but the injector firing order will not match--the car will still run, but it's not ideal. The older block will not accept a regular roller cam (like a B-cam or whatever) without expensive conversion lifters. You can put a 351W camshaft in it if you want the correct firing order.

-Your balancer and flywheel are not the right imbalance (you're right about the 50 oz), so pre-81/351W balancer and flywheel will have to be purchased.
The earlier crankshafts are stronger, but they and the blocks they fit are designed for a two-piece rear main seal. Two-piecers leak a little more easily.

-All your accesories will fit just fine as long as you use a balancer that is made for a serpentine belt drive, like Ford's M-6316-k351.

-Here's one you probably didn't see coming: your dipstick isn't going to have a home. The '72 block is not fitted for a block-mounted dipstick. The easiest fix for this is a Canton or Moroso oil pan that has a provision for the dipstick built into it.

-You'll have to change the gear on your distributor b/c it's made for a steel billet camshaft. It'll eat up the iron flat-tappet cam and make a mess inside your engine. Have a machine shop install the gear because it has to be oriented properly on the distributor or it will not mesh properly with the cam.

I'm pretty sure that's everything, have I convinced you to buy a late model shortblock yet? Remember, you can get a motorsport shortblock for around $1300 (M-6009-b50), and all your existing stuff will work without a hitch.

 

[5LugFoxFanatic]

Wow, that's alot of good information, thanks for the reply!

 

[nosmatt]

excellent response.


i would highly advise a rering kit at the least. 250 bux. need some hand tools, and some time. or, bore it, and do a full on rebuil;d, expect to pay about a grand. this is if you do it yourself. but, that is good parts, no china junk. or, build a 331/347 w/china junk for about 300 more.

 

[Fishhawk]

If I'm not mistaken the water pump is also different. The newer 302 uses a reverse rotational impeller which may change how water is circulated through the older block. If you use the earlier water pump the radiator hoses for the earlier engine won't line up with the late model radiator. It has been a hundred years since I owned my 68 and I'm not 100% on this, but at least you should check into this area.

 

[joncash]

Hey, no problem.

The water pasages in the block are the same, you just have to use the right timing cover and water pump for the year of the car. In other words , reuse the stuff off the original motor.