Upcoming FE build: plan coming together

[cscobra]

Nothing wrong at all with a 390 block. In stock form, it has the same stroke as a 427. For easier and higher revs, as well as better durability when you're not revving it, a shorter stroke (390/427) with lower piston speeds is a better choice than a longer stroke (428 and/or stroker kit on any engine) with its inherently higher piston speeds. Any of these engines will have far more power (especially torque) than can be realistically used on the street, and plenty of power for racing, so why not enhance reliability, durability, and longer engine life if you can?

As far as originality goes, the 390 and 428 blocks are externally identical. The 428 block was installed on far more Cobras than was the 427. Remember, the first couple of experimental FE-block Cobras even used 390 blocks (albeit aluminum). So again, no problem using a 390.

Remember also to not use a carburetor that is too big for the engine. Holley's website has a calculator to help you determine the size that would be best for your needs.

Frankly, I hope no one here takes my advice! That way, 390 blocks will continue to be cheap (and relatively plentiful) for guys like me!

[lemans24]

if you do webers, make sure you use the right cam and install O2 bungs in the exhaust collectors. An LM-2 makes it alot easier to see whats going on with the air fuel mixture. I'm running 48IDA's on mine. Still working out the fine tuning, but it is awsome. I got mine from Pierce Manifolds. They have been great to work with.

[patrickt]

Originally Posted by lemans24

if you do webers, make sure you use the right cam and install O2 bungs in the exhaust collectors.

That's a smart idea. AKS801 - If you're running Webers then you're likely thinking about revving your engine a little higher than the average FE build. You might want to open the "should I install a solid cam" can o' worms. FWIW, I went with a shorter stroke (4.125) on my build and the bore just .025 over. Along with an aluminum flywheel, the solid flat tappet lets it rev past six grand without blinking an eye. Others will tell you that a solid flat tappet is just a PITA, so you'll have to weed through the BS and decide for yourself.

[aks801]

Ah-yee... so much to consider!

Maybe I should just pick up a used Hyundai Tiburon, slap some nitrous to it, and be happy.

Nah!!!!!!!!!

[Gunner]

Originally Posted by aks801

Maybe I should just pick up a used Hyundai Tiburon, slap some nitrous to it, and be happy.

When I was done with my Mustang (it's at the build-a-kit stage, all parts present and accounted for, some assembly required) I realized I could have walked into a Subaru dealership and driven out in a WRX STi for a little less.

Yeah, riiiiighhht.

[patrickt]

I think a 390 is probably just as good as a 428 in most of our cars. By the time you stroke and bore them, neither one is what it was anyway. Just try and find one of the later 390 blocks that have the extra webbing on the crank saddle -- some have it, some don't. I'm thinking (now don't quote me) that all 390/428 blocks were getting that around 1971 or so (service blocks), ribs on the outside too, at least on the 428s. On the earlier 428 blocks you couldn't always rely on the scratch marks on the back of the block, you actually have to look at the bottom end with your own two eyes.

[Gunner]

Originally Posted by patrickt

I think a 390 is probably just as good as a 428 in most of our cars.

Barring the resale issue. You could build a fabulous motor around a 390 block, better than most FEs around... but convincing a buyer it's "as good" will be an uphill battle when he's looking at 428 and 427 cars.

Does it make sense? No. Is a 390 in any other way a bad choice? No.

Builder's choice... pays yer money and takes yer chance. You could, of course, lie at resale time... :P