Forte 363 with a T56 possible?

[ChasNMe]

I'm getting a 363 from Mike and right now I'm getting the TKX also. I have the IRS Rear from F5R with the standard 3.55 gears and will be running 315s in the rear. Pretty sure I opted for the 0.81 top gear on the TKX on Mike's recommendation. I will be doing some highway driving and feel like I will be in the 2500-3000 rpm range so I was thinking about the extra gear with the T56. I would rather have two overdrives so was thinking about the T56 instead of the TKX. How much shorter of a driveshaft will it need to be and is it even doable? Would I just be inviting drivetrain issues? should I leave well enough alone with the TKX?

Mike said he knows people have shortened their driveshaft when using Coyote engines with the T56 on a roadster, but didn't know of anyone that has used a T56 with the 363 . . . . He thinks it would be too short, probably so, and I don't know the ramifications of that. Is it feasible, where do I get one or who can do the modification to my driveshaft? any help is appreciated . . . .

also a video for your time . . . . My engine . . . .

https://youtu.be/t7ePuu0WtnQ

thanks, Jake

[edwardb]

363 is the same size as 302, 303, 331, 347, etc. The difference is internal. Yes, a T-56 will fit in a Roadster with IRS. It's a little tighter with a SBF compared to a Coyote (which is a bit shorter) so the driveshaft is short. But with IRS it's OK since the diff doesn't move. Haven't personally done it (my T-56 is in a Coupe) but from I understand the T-56 requires a mod to the e-brake (possibly relocate?) and a mod to the transmission A-frame. I had a Roadster with a TKO (predecessor to the TKX) and the 0.82 5th gear. I wasn't a fan. For exactly the reason you mention. High RPM's at cruise. How are you planning to use the car? Curious why Mike would recommend that ratio unless you have a specific reason. Agree the T-56 is nice with two overdrives. But a TKX with the .68 5th gear is an excellent choice as well.

[David Williamson]

The other option is the .6x OD TKX. I have the older TKO 600 version with my Dart 363 in a Gen 3 coupe and it works well. 5th is a good gear on the highway 2200 - 2300 RPM and 4th is great for passing
David W

[Jim1855]

In the past I ran the TKO-600 with the .6x OD and 3.27 gears. Used 1st to launch, 2-4 for driving and 5th for cruising. 2,200 at 80mph. I liked it and will be using the same for this build except 3.31 gears.

The T56 would be great but... It's heavier by about 35#, wider, longer and more expensive. But then having 2 ODs would satisfy the OD question. The Tremec website has the specifications and dimensions.

Jim

[MB750]

Personally, I think you should leave well enough alone and stick with the TKX.

FYI, back in the 90's I had an 88 Mustang GT with 3.73's and it spun 2100 rpm at 70 in 5th. Stock T5. I think you'll be happy with the cruise RPM.
With the 2.73 it came with I was at 1500 rpm.

Curious, what's the compression ratio on that engine? And the cam specs?

[rich grsc]

I would think the easiest and least expensive would be to get the TKX with .6 OD, next would be to swap to a 3:31 rear gear set. With a 363 hp & torque I wouldn't have picked 3:55 gears, and neither would I have used a .81 OD. As hp & torque go up the gears can come down

[MB750]

I would think the easiest and least expensive would be to get the TKX with .6 OD, next would be to swap to a 3:31 rear gear set. With a 363 hp & torque I wouldn't have picked 3:55 gears, and neither would I have used a .81 OD. Has hp & torque go up the gears can come down

Yea, I agree with this. With as much power as your engine has with those gears I'd be more worried you're gonna run out of 1st before you get through the intersection than having high revs on the interstate.

[ChasNMe]

I will be driving both around town at 40-50 and on the interstates a bunch at 75, so I'd like the best of both worlds. If I understood Mike, which maybe I didn't, it had to do with the large drop off going from 4 to 5 with this engine and maybe not being great at speeds around 55.

I read lots of builds and seemed like most were getting the 3.55 so I went that route. Certainly in hindsight I should have done more research, but not knowing how different engines affect it . . . you don't know what you don't know . . .

My brother is a ford guy, he thought this cam would be better than the E cam Mike normally uses . . . .
COMP Cams Xtreme Energy Camshafts 35-351-8
Camshaft, Hydraulic Roller Tappet, Advertised Duration 270/276, Lift .512/.512, Ford, 5.0L HO, Each
not sure what the compression is, I'm looking forward to putting this engine in

Any idea about shortening the driveshaft . . . how much shorter it would need to be, who can do it? I'm not sure I understand exactly how being shorter effects it, I mean its only about 9" or so anyway . . .

[Jim1855]

Shortening the driveshaft shouldn't be that bad. Find a good shop that builds them and have them do it, there's welding and balancing required. It's easy to get a measurement if the engine is in otherwise change based on the difference in the trans length.
Jim

[MB750]

WOW, I am really surprised your engine is pulling those numbers with that cam. Don't take this the wrong way, the proof is in the pudding as they say, but those cam numbers are rather mild. Just over half an inch of lift and duration in the teens (at .050"). FYI, advertised duration is measured as soon as there's lift at the valve. Typically the industry recognizes the duration at .050" lift.

Regardless, that's a solid engine. And peak torque at 3500 RPM! That car is really gonna plant you back in the seat when you gas it. I'd still like to know the CR if you can get it. I'm guessing it'll have a pretty constant diet of 93 octane (or whatever's highest in your state at the pump).

I'm also excited because those are the same heads I've put on my SBF 306.