454SS in okc

[kevhill85]

The photo in your sig is the one seen many times. I almost put vette whee.s on mine..

 

[454SSguy]

Most will tell you a strong T56 does not exist for these trucks (based on the weight of the truck). I have run a T56 for about 11 years behind a 461ci, 505 hp/535tq BBC and put roughly 45,000 miles on the combo. Right now the trans is out due to a damaged 2nd gear syncro. About 4 years ago I tore up the syncro keys for 4th gear. Both fairly cheap fixes. The truck is soo much more fun with a stick in it vs the TH400/3.73's (I have 4.56's in the 14 bolt now). It is also much more economical with the overdrive and 4.56s. I get 17mpg on the highway. Don't be scared of the T56 swap. It is easier than you think.

GV is a great solution if you want to keep the TH400. There is only a few gear choices for the 9.5" 14 bolt, and the 3.73s without overdrive get real old real quick. A 4L80E is cheaper to swap, but you need a controller. The GV offers gear splitting, which in effect gives you 6 forward gears.

I used to have the same rediculous tail light setup on mine, but I used the bolt in tail light fillers (thank god) and was able to switch back without any bodywork. I thought the 'vette tails were cool (when I was 20), but later decided the factory (tinted) tails were better. I have owned my 454SS for 20 years and it has gone thru many transformations.

Welcome to the site.

Thanks for the encouragement. Your truck gets talked about consantly on the 454SS site anytime the manual tranny is brought up. I will definatley be picking your brain when I do the swap (which I have decided on for sure).

 

[SixSpeedSS]

Thanks for the encouragement. Your truck gets talked about consantly on the 454SS site anytime the manual tranny is brought up. I will definatley be picking your brain when I do the swap (which I have decided on for sure).

I'm certain there is some negative responses about my truck on there as well. I haven't visited that site in a few years, but I do still keep close with a few people on there.

I'd be glad to give you some input. If you want to build a nice street truck, then the conversion can be done fairly cheap. If you want an all out drag truck, then the conversions will not be cheap. My truck is primarily a street truck that gets drag raced once in a while.

 

[454SSguy]

I will be doing a boosted 468-496 CI motor. Nothing crazy looking at 550-650 at the wheels. I'm gonna go ahead and upgrade all the syncros and forks before I put it in. Anything else I should consider?

 

[Txwildman]

Bad aSS!!!!

 

[SixSpeedSS]

I will be doing a boosted 468-496 CI motor. Nothing crazy looking at 550-650 at the wheels. I'm gonna go ahead and upgrade all the syncros and forks before I put it in. Anything else I should consider?

The main issue is the clutch/hydraulics/flywheel. If you do not need to do 5000 rpm launches, then you can get away with an LT1 style T56 with the OEM bellhousing/clutch/hydraulic slave cylinder, using a flywheel designed to go on a 2 pc rear main seal motor (if you are running a two piece - original 1990 MarkIV block). The whole setup is bolt together this way. It almost seems factory. There is some effort to adapt the GMT400 master cyl/pedals to the Fbody slave, but not a big deal.

The only issue this way is having a clutch that can handle a big motor and the weight of the truck. Again, if you really only plan on street driving, then you will have years of fun with it. If you want to drag race it every weekend, then you will ahve a tough time finding a clutch to handle it. Currently I have mine apart and the clutch disc is cracked thru the center. I am going to my 4th clutch since I fisrt built it. My truck is primarily a street truck that I drag race once in a while. The clutches have been fine on the street. In fact I ran a stock LT1 clutch for 5 or 6 years before deciding I needed MT ET Street radials.

BTW...I have only 398hp at the wheels. If you want 550-650 at the wheels, then you should not be looking into a T56 swap. A Richmond OD would probably be your best choice. These trucks are waaay too heavy for the T56 at that power level. Now the only damage I have done to my stock LT1 T56 is syncros, I would imagine at a higher power level, you are gonna break some hard parts real easy.

Do you want to 'know' that your trans choice can handle the power or 'hope' it can handle the power. There is always a weak point when running a manual trans.

 

[454SSguy]

i definately feel ya on the know/hope concept. My 04 GTO with a T-56 held up for over a year with over 650 to the wheels, but I was hoping the whole time if you know what I mean. It also got raced quite a bit. I really think the T-56 is for me, gonna do an upgrade and if I start shelling them, then I'll consider 5k for a richmond. Wont be doing any "dumps" with this truck btw, and it will never see the track. My last car turned into a racecar (the goat) and it just wasn't fun anymore.

 

[SixSpeedSS]

i definately feel ya on the know/hope concept. My 04 GTO with a T-56 held up for over a year with over 650 to the wheels, but I was hoping the whole time if you know what I mean. It also got raced quite a bit. I really think the T-56 is for me, gonna do an upgrade and if I start shelling them, then I'll consider 5k for a richmond. Wont be doing any "dumps" with this truck btw, and it will never see the track. My last car turned into a racecar (the goat) and it just wasn't fun anymore.

If you stick to what you're telling me, then the LT1 T56 conversion is the cheapest/easiest way to get it done. It will hold up just fine in stock form. You need a flywheel (Centerfoce, SPEC, Fidanza, etc all have a LT1 style that will bolt on a Mark IV 2 pc rear main seal motor), a decent clutch, an LT1 trans (preferably '95-'97 with .50 6th gear), LT1 Bellhousing, GMT400 truck master cyl, LT1 slave cylinder, and some small parts to adapt the line from the master to the slave from Advance Adapters (link below)

http://www.advanceadapters.com/products/pn-716124/ this fitting will go in the fbody LT1 slave cylinder, then...
http://www.advanceadapters.com/products/pn-716130h/ this line will screw onto the fitting (elbow end) and go up to the steel line from the master cyl (I made a steel line and got an auto parts adapter to connect the steel line to this line)

The rest is common sense. Stock crossmember, GMT400 pedals (an extra bracket for mounting the pedals may need to be added to the firewall, but your truck may have it -- mine did not), new driveshaft, speedo will not be correct and could be prgrammed if needed.

This swap is actually quite easy. A little pricey, but well worth it in the end.