Straight-6 to V-8 Engine Swap in 1975 XB

[March Hare]

.. this question is for anyone that might have attempted this before.

How extensive is the difference between the motor mounts of the factory Straight-6 and a V-8 / 5.7 for the 1975 Falcon XB

Does the frame cross-member (k-frame) need to be changed or just the motor side mounts, or both?

[MrSpeed]

As long as you fit a 302/351 cleveland all you will have to change are the engine mounts, it would be a good idea to have the brace of the K frame strengthened,all related transmissions C4/10,fmx auto, single rail borg warner, toploader manual will bolt up to the gearbox mounts under the car, i dont know if the yoke on the diff will except a uni from a 9 inch prop six cylinder cars have a single heat shield under the floor pan, where V8 cars have twin, this can be made from a patch panel and welded into place, the front springs will also need to be upgraded from 6 cyl to V8.

Cheers
Simon

[torinoscj]

The frame stands that the motor mount bolts to are different between 6 and V8,but since they are bolt on pieces,you just need to get some.I have a spare set of V8 stands here in Oregon if you need them.The trans crossmember can be moved forward or back depending on the trans used.If you are doing a V8 conversion,get a 1970/71 Torino/Montego/Fairlane 9" rear end.It is a direct bolt in other then the main brake line for the XB is on the left side and the Torino is on the right.So either get a custom,long flex line to the splitter or move the splitter and lines from the XB 8" onto the 9".I have a bunch of these rear ends also,but shipping could be a bit to Nevada.Once you have a V8 and 9" under it,just get a Torino/Mustang/Montego/Fairlane/Cougar drive line and have it cut down to fit.It is easier and cheaper to cut one down then have a new one built.Make sure the U joint size is the same for the driveline as the rear end.What motor/trans are you installing?Cheers,Bill

[.MAD MAX.]

Bill....question about the 9" diff: the US bolt ins obviously are not disc brake set ups, any idea if the backing plates etc from a BW diff would fit?
Doug

[March Hare]

.. thanks to you guys for responding.. but I was out-bid last night.. was thinkin' bout making an Yellow Interceptor replica with this:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 3AIT#v4-14

[torinoscj]

I don't know if the backing plates and drums would swap from the BW to a 9",it would depend on the shape/size of the housing end flanges,but since a BW is an integral style rear and the 9" has bolt in axles instead of 'C' clips,I would guess no.Cheers,Bill

[.MAD MAX.]

I don't know if the backing plates and drums would swap from the BW to a 9",it would depend on the shape/size of the housing end flanges,but since a BW is an integral style rear and the 9" has bolt in axles instead of 'C' clips,I would guess no.Cheers,Bill

Thanks Bil...... I would prefer to keep mine rear discs so i'll either find a diff from here and then swap on some Aussies rear discs or wait until I find a decent compete diff from one of the suppliers.
Doug

[torinoscj]

Hey Doug,the Aussie rear discs are a total PITA,the rotor is held onto the axle end by the wheel studs,are only 28 spline and require a special deep cup clamp to remove the axle bearing,which is also an Aussie ONLY part as it is a double width bearing.You would be much happier getting a set off of a 95 and up Exploder.Even though it is an 8.8,'C' clip style rear,the disc brake stuff will go right onto a 9" rear end,or you can just get the Motorsports kit from Ford or REALLY step up and get some Wilwoods.
You should look into getting a set of 31 spline axles so you don't twist the splines,like I did at the track.Plus 31 spline Traction lock third members with 3.50:1 gears are standard in most late 70's Ford 4x4 trucks and Bronco's and are fairly cheap.Cheers,Bill

[MFP1]

The frame stands that the motor mount bolts to are different between 6 and V8,but since they are bolt on pieces,you just need to get some.I have a spare set of V8 stands here in Oregon if you need them.The trans crossmember can be moved forward or back depending on the trans used.If you are doing a V8 conversion,get a 1970/71 Torino/Montego/Fairlane 9" rear end.It is a direct bolt in other then the main brake line for the XB is on the left side and the Torino is on the right.So either get a custom,long flex line to the splitter or move the splitter and lines from the XB 8" onto the 9".I have a bunch of these rear ends also,but shipping could be a bit to Nevada.Once you have a V8 and 9" under it,just get a Torino/Mustang/Montego/Fairlane/Cougar drive line and have it cut down to fit.It is easier and cheaper to cut one down then have a new one built.Make sure the U joint size is the same for the driveline as the rear end.What motor/trans are you installing?Cheers,Bill

Hey Bill, this is really useful. Looks like we will be doing a 6-cyl sedan soon (converting to V-8) so I may try and talk you out of those stands....

[Big Bopper Bart]

.. this question is for anyone that might have attempted this before.

How extensive is the difference between the motor mounts of the factory Straight-6 and a V-8 / 5.7 for the 1975 Falcon XB

Does the frame cross-member (k-frame) need to be changed or just the motor side mounts, or both?

5.8.....5.8 How daare you besmirch the cubic inch displacement of a Ford why,its not some pewter block having chevy