My friend wants to sell me his 1973 454 long block for $300. His cousin is selling Brand new Cast 502 heads for 800.00. Was wondering if this combo will work and how much power I can expect to get. Im looking to drop this into my 69 basket case.

Also while I have your attention, my friend offered to give me his 396 crank. Should I destroke the 454 (427?) and if so what is involved with doing this. The only engine building experience I have I building a couple of small blocks (factory specs.. never played with stoking), and assembling my 502.

thanks

Tom

A $300 long block 454 is very likely a good deal, depending on condition. It'd have to be pretty bad to not be worth that.

The 502 heads are rectangular port units, I suspect you'd be happier with ovals. Price isn't bad, but it isn't that great, either.

Pass on using the 396 crank. You'll want all the torque you can get.

your block is a mark 4 block and the 502 heads are mark 5 and mark 6. they have different water passages. I know they use to make a gasket to run older heads on the newer blocks but I`m not sure about newer heads on older blocks. better do some research before spending any money. if the heads will work and are square port, I would leave the 454 crank in there since you`ll loose some low end with the square ports. otherwise a 427 is a great street/strip motor and should make plenty of power for you.

New heads on an old block shouldn't be a problem if you're careful about coolant routing.

ALL Gen V/VI engines use a smaller coolant passage in the gasket at the rear of the engine, and three small, (about 1/2 inch) round holes at the lower edge of the block deck, between the cylinders. If your Mk IV block has those holes (some do, some don't) or if you add those holes, use a gasket that also has those holes.

If you don't have those holes in the deck, you need to use a gasket that has TWO coolant passages at the rear of the engine. They are odd-shaped, and one is larger than the other. It's the big one that's deleted when the three small holes in the deck are used.

If you don't have the holes in the deck, and you don't have the two passages in the gasket at the rear, the engine will overheat and you'll spend the rest of forever trying to figure out why.

Other than coolant routing, the problem is trying to use OLD heads on a NEW block, which can lead to coolant leakage into the lifter valley.

I'd grab the shortblock for $300 and look for a pair of oval port heads

Ok... Heres the Deal.. I just found out that the heads are still on the motor and comes with the deal. Here are the numbers.

Block 3999289
Heads 336781

Is this a good combo?

I wanna build a quick street car and need some recommendations (cams,intake, head work, etc) on what to do to get the best performance without Boring the block and spending thousands as I found out the bottom end is in real good shape (new bearings/rings).

thanks

Tom

Originally posted by nebula72:

Block 3999289
Heads 336781

Is this a good combo?

..for $300,thats a SWEET deal
Those heads are perfect..just add the 2.19/1.88 valves and do so a little clean up,and you'll have a great set of heads.
781's and 049's are some best flowing open chamber BBC heads

What valves came on the heads originally. Will the 2.19/1.88s fit in my heads without any mods? Sorry for my ignorance on this.

Tom

Those heads originally came with 2.06/1.72 valves. You will need to have the valve seats cut larger to have the valves installed.

Daniel

Nebula, Negative, machineing and $$ needed

How much should i expect to pay to get it done?

Tom