4spd to Turbo 400

[custodian]

I'm contemplating in changing my 86 C30 2wd 454 with the 4spd with granny gear to a Turbo 400. Has any one done this swap?

 

[bucket]

Lots of people have. Have any specific questions?

 

[custodian]

Lots of people have. Have any specific questions?

When I got the truck, I thought having the hydraulic clutch would be easy on my old bones, it's not.

Are the mounting holes for the trans shifter hardware on the frame?

Will I have to get a trans cross member?

I have a two piece drive shaft, will that stay the same?

I have the Dana 70HD rear with the 4.10 ratio, I know that highway RPM's will be high, will this bother the 454?

Is there any resale value of the 4spd and all the clutch related items?

 

[Turbo4whl]

Since the T400 and the SM465 trans both have a final drive of 1:1, you will only gain 2 to 300 RPM highway speed with converter slippage. RPM not much higher.

 

[custodian]

Since the T400 and the SM465 trans both have a final drive of 1:1, you will only gain 2 to 300 RPM highway speed with converter slippage. RPM not much higher.

Thanks, good to know.

 

[Turbo4whl]

Thanks, good to know.

Of course, if you have a full weight load in your 1 ton, you will have more slippage.

 

[custodian]

Of course, if you have a full weight load in your 1 ton, you will have more slippage.

I'm not using the truck as a work truck, just something different to drive around with the granddaughters is their C10's that I gave them.

 

[Ricko1966]

You will also lose your low 1st gear. If you always used 2nd it won't mean anything to you,but if you used 1st much you may miss it. Your crossmember should work,may need a different mount,may need a drive shaft,there are 3 different lengths of 400s so you'll need to check the length of the transmission you have vs,the length of what you are installing. You are going to have to figure out how you are going to shift it and how you are going to kick it down,but that's easy. Personally I'd use a shifter like a Hurst Indymatic,B&M unimatic,etc run a 4 speed shift boot and hold my clutch pedal up with a spring. The truck would look right,cheaper and easier than swapping pedals and columns .

 

[bucket]

When I got the truck, I thought having the hydraulic clutch would be easy on my old bones, it's not.

Are the mounting holes for the trans shifter hardware on the frame?

Will I have to get a trans cross member?

I have a two piece drive shaft, will that stay the same?

I have the Dana 70HD rear with the 4.10 ratio, I know that highway RPM's will be high, will this bother the 454?

Is there any resale value of the 4spd and all the clutch related items?

When I swapped one, I had to have the forward portion of the driveshaft lengthened, iirc. I used the same crossmember, but I don't remember if it used the same holes, a different set of holes or if I had to drill holes. The reason I don't remember is because it was no big deal at all and it's been many years. I went with a B&M Unimatic shifter for the simplicity... no swapping steering columns or anything.

The 465 trans has some value, but not much. Yet. The hydraulic pedal assembly is worth 300+ these days, but there's no need to swap it out if you don't mind the extra pedal. The hydraulic bellhousing is worth around 100 bucks I think.

 

[JBswth]

I'm contemplating in changing my 86 C30 2wd 454 with the 4spd with granny gear to a Turbo 400. Has any one done this swap?

Easy enough to do, but you have to consider your rear axle ratio. Automatics allow the engine to pull taller gears, plus they generate some additional RPM as well, so you will probably find your truck to be undergeared, so that it is revving hard at freeway speeds if you use the same gearing as you used with the stick. Unless you are not concerned with freeway manners, I would use a 3:73 rear end with a Turbo 400.

J. B.