331/347 vs 392/408...which one?

The weak point of the 302 based engines is the block...The 347s make very impressive power for their size but most would agree a stock blocked engine is living on borrowed time around 450hp and up if you are pounding on it regularly.You could buy an aftermarket block and live happily ever after or.....Is this an all around car or are you looking for max performance?....The 351 based engines can be made to look like an FE if that is something you would like for the cobra..You can get adaptors to run the FE valve covers on the windsor and they also now make a dual quad intake for the 351....The 351 based motors will make tons of torque and you won't need to rev them so high to make the same power...Thats not to say they can't be made to rev quickly if your after max performance......The good news is I don't think you can go wrong either way depending on what you want from the car...450hp or more in a cobra is gonna be a handful :

I say that it depends upon your budget. Considering that you're building an AC Cobra replica, I'd assume you have a decent budget. Therefore I vote for the displacement...make it feel more like an original big-block.

The cheaper route is a stock 351W block and a 4.00" crank to make a 408. The more extreme route is an aftermarket block with a 4.125" bore and a 4.00" stroke crank for 427 c.i.d. (Coolest option IMHO).

Either way, I would limit stroking a Windsor to 4.00" max so as not to give up too much in the way of piston compression-height.

Combined with the right top-end, this will make for a lightweight package that will perform and feel like a big-block.

Frdnt, I didn't know that they make adapters to run FE valve covers on a Windsor... how cool is that??? Where can I get some?

Here is one place...I think there is more than one though..
Windsor Valve Covers I even saw the old FE style expansion tanks that bolt to the front of the engine around somewhere for the windsor...

408 - Check ADPerformance.com Brian is well known in stroker community

Here are links for best price/info I have found for valve adapters and nice guy.

SuperHart's Home PageMy COBRA Project
VALVE COVER ADAPTER & DUAL QUAD INTAKE PAGEVALVE COVER ADAPTER COMPLETED PROJECTS
VALVE COVER ADAPTERS INSTALLATION INSTRUCTIONS

Originally Posted by Thordane65

What Chassis???

65/66 mustang/falcon etc- 347
67-up mustang, etc - 408

Im partial to 347... lighter, rev like mad and there are tons of parts available.

+1

This is my formula for my 1966 and 1967 Mustangs...because fit and accessibility are high priority with me.

No 427 for sure. and its got nothing to do with power. Everyone want to hear a cobra has a 427.

I have a cobra with a 393, so I know. Just my experience.
I wished the car had a 427, small block or not.

^^I agree...^^

Originally Posted by frdnut

The weak point of the 302 based engines is the block...The 347s make very impressive power for their size but most would agree a stock blocked engine is living on borrowed time around 450hp and up if you are pounding on it regularly.You could buy an aftermarket block and live happily ever after or.....

I have a Mexican block 302. Same as a Hi-Po 289. Large beefy mains, and they have more meat in other areas as well. Great base for a stroker motor in IMO.

I think most of the older stuff is probably a little better quality than Late 70's-90's stuff. Seasoned cast iron, so to speak.

I could be wrong though. It has happened, once....

The Ford 289 and 302 Engine Block

Excerpted from the article above -

"One alternative, though not always easy to find, are the 302 blocks cast in Mexico. A number of these blocks found their way into U.S.-built Fords and Mercurys. These Mexican blocks weigh more, but they offer strength in a heavier casting, thus being more suitable for high-performance use."

Some example images and comparisons.

None of my engine customers have EVER blownup a stock 289 or 302 block. The HP range is fom 450 to 530 with revs up to 7000 RPM I keep hearing about the block cant take nmore than 450 HP, but I do NOT believe it,Of coarse, I always dyno tune my engines and break them in correctly before they get them. Perhaps this is why they dont break them. A have done many 347 strokes for Cobra kit cars, and one 408 stroker that made 550 HP. I would use the 347 as my first choice in any small car( Mustang, falcon, whatever)

JOE SHERMAN RACING ENGINES