[tigertim]

I just joined today. I have a 78 King Cobra. It was in sad shape when I got it, 12 years ago. I have slowly broght it back to life. It has the 302 in it. I want to put a 351w in it. Will the mustang II flywheel bolt on to the 351w crank ?

[pcfrisch]

Welcome to AFM! check out the tech areas.

[stlwagon]

Welcome aboard... Let's look in here for help.

[COBRAIIW]

I have done this. there are fitment issues since the 351W is a little taller block, and over an inch wider.
Clearance is needed over the rack and pinion in the oil pan area, and it has to be reshaped a little for the starter.

[COBRAIIW]

And yes, the flywheel will fit.

[2Manystangs]

You need to make sure you have the flywheel balanced correctly to correspond to your 351...302s came in two varieties 28/50 oz...you can change the weights...it's the headers that are the challenge...I would recommend you just keep your 302 and build a stroker 331, building a 351 is pricey, I know, I'm doing one.

[T. Hadley]

So COBRAIIW, what headers are you using, and is there any hood clearance issues?

T.

[COBRAIIW]

I am using a set of old Blackjack headers for the MustangII.
They don't make them anymore as far as I know.
If you use a low height intake, and no carb spacer, and a thin air cleaner, there won't be a need to cut the hood.
It IS very close however.
I went with a "Offenhauser 360" midrange style intake, with a 1 1/2" spacer, and a 3"x13" air cleaner on top of the Holley 670cfm DP.
Yes, I needed to cut the hood, and use a reverse style scoop.

The headers also needed to be "modified" at two places.
The number 7 pipe crosses over top of the number 8, and hits the corner of the power brake booster. Not an issue if you don't have one.
Also it hits down at the steering arm.
Making flat spots on the headers in these ares solves this, and minimally affects the flow.
The other modification was to cut out the sections of the fehderwells where the headers come into contact, and put in a patch in those areas. The cam I have insisted I do it!

[COBRAIIW]

Added pics.
Yes, it's still a work in progress, but I'm somewhere over 300hp right now.
351W with 10-1 pistons, roller conversion, ported and milled 302HO heads with large valves, crane thumper cam, offenhauser360 intake, holley 670cfm DP. Block bored to .040 makes it 358cu in.

[T. Hadley]

Very cool and thanks for the Pics, They were very helpful, I may have to look at doing a 351 again, The one thing that kept me from doing it, was the swap headers that run some of the tubes under the front crossmember, the car sit's to low for that and I'm not going to raise it.

WE have the Hooker headers, have you ever tried them with a 351?

T.

[tigertim]

Thanks for the info. What year did the 351w switch from the 28oz. to the 50oz. flywheel ? I think that the max H P for the bottom end of a 302 is 425, is this right ? What is the max H P for a 351w ? I bought a spair hood, knowing that some day I would be going with an aftermarket intake and carb, so that I could save the original

[COBRAIIW]

I am not sure what year the 351W changed to 50 oz.
I actually didn't know that it did.
My block and crank are the 70's version, using 28 oz.
The C4 trans with the Mustang II flexplate bolts right up.
The RAD4 manual trans, flywheel, pressure plate, and clutch also bolt right up.
Don't forget to route the clutch cable AWAY from the headers, I learned the hard way.
You can probably modify the Hookers to fit the way you want, if your handy with a welder, or find an exhaust expert who will.

I have seen stroker kits that will bring you up to 427cu in.
My guess is the 393cu in kit is safer.
The kit manufacturers will give you an estimate of horsepower .