hpfiend Posted June 10, 2016 Report Share Posted June 10, 2016 Hey all- I am looking to put a gt45 turbocharged LS 5.3 in a 2700 lv amc gremlin. I need it to reliably hold about 650 rwhp. Will a th350 handle this? If not what type of th400 do I need? They are all over craigslist these days. Thanks! Andrew Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
STEVE-O Posted June 10, 2016 Report Share Posted June 10, 2016 I take it this is a drag set up? I ask because a stock 4l80 should handle that power but as a drag car not the BEST choice of a trans Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 10, 2016 Author Report Share Posted June 10, 2016 Yes a drag racing car- can you put a manual valve body in those? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
STEVE-O Posted June 10, 2016 Report Share Posted June 10, 2016 Yes a drag racing car- can you put a manual valve body in those? Sent from my iPhone using Tapatalk Yes but if it's a drag set up no real need to have the overdrive gear so a th400 similar to say what ray or Dan run etc is all that is needed ( obviously don't need one to handle their extremes or gears) Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 10, 2016 Author Report Share Posted June 10, 2016 Good point Quote Link to comment Share on other sites More sharing options...
Geeto67 Posted June 10, 2016 Report Share Posted June 10, 2016 A stock TH400 will hold reliably 400hp/450ft lbs of torque. So you aren't looking for a stock th400. A stock 4l80 will hold about 800ft/lbs torque but as pointed out the gearing isn't ideal for a drag car. Are you looking for the cheapest? Simplist? Lightest? Easiest to install? What's the budget? Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 10, 2016 Author Report Share Posted June 10, 2016 Mix between cheapest and most simple! I am considering starting over from scratch with our spare gremlin with the parts I have acquired for the current gen 1 sbc swapped version I have. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Geeto67 Posted June 10, 2016 Report Share Posted June 10, 2016 just pure cheapest price for the unit would be a stock 4L80. But that creates a lot of problems on it's on because it is also the heaviest and the largest. When I did the TH400 in my GTO a loooong time ago, I found the best setup was to find a local shop and build it using TCI parts. I spent $1500 in 1990's money to do it proper and the only issues I ever had with it were a ballooning converter when I was standing on the line lock and a leak at the right side shift modulator which I fixed with some teflon tape. I do run a massive trans cooler built into the custom aluminum radiator so that helps. Whether you buy a cheap TH400 core and have it rebuilt locally or you buy an off the shelf new TH400 I don't see you getting out of this for less than $1500-$2K to do it right. If you can rebuild a transmission yourself the kits from TCI are about $300 -$500 depending on options (trans brake kits usually run about $500) but there are some tricks that re-builders just know with these things. FWIW I would consider this: https://www.summitracing.com/parts/tci-211005/overview/ For about $1550 you get a trans with a 30 day warranty that you can pick up at summit and drop in your car that afternoon. It's not a bad way to go. Quote Link to comment Share on other sites More sharing options...
Nickey4271647545519 Posted June 10, 2016 Report Share Posted June 10, 2016 Stick with a 350 or 400. Both can be built to handle that power easily. As far as wanting a manual vb, i would never recommend putting one a GM O/D trans, they seem to have very high rates of failure when done. Considering the weight of the gremlin, I would pick TH350 get a nice tight custom spec'd converter and let it eat Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 10, 2016 Author Report Share Posted June 10, 2016 I have a Jegs built th350 in it now.m with a non reverse manual Vb. 1st and 2 are good, third is ridiculous. 3000 rpm stall I think. Only 3.73 rear gear now though. I didn't think it could handle that much power--- awesome Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
cdk 4219 Posted June 11, 2016 Report Share Posted June 11, 2016 A stock TH400 will hold reliably 400hp/450ft lbs of torque. So you aren't looking for a stock th400. A stock 4l80 will hold about 800ft/lbs torque but as pointed out the gearing isn't ideal for a drag car. Are you looking for the cheapest? Simplist? Lightest? Easiest to install? What's the budget? A stock rebuilt th400 will hold considerably more than that power, especially with a 2700lb car. Upgrading clutch material will take you well past the 700whp mark. The turbo 350 can be built to take the a use, but it will cost much more. The only downside to the 400 is parasitic loss and weight. If it is a higher HP car and light a powerglide 2 speed will be the best bet. Any turbo 400 from Craigslist will more than likely have to be rebuilt, as the last time they were manufactured for production was in the late 80s. Figure that into the total cost if you can't rebuild yourself. You will also need a converter, transbrake, and manual valve body. A new Hughes powerglide Starts at $1500, with all brand new parts. Quote Link to comment Share on other sites More sharing options...
jesselee83189 Posted June 11, 2016 Report Share Posted June 11, 2016 take it from me, i have entirely tooo much money in my th400. wish i woulda just got a stock 8 bolt th400 and upgraded the sprag and clutches. i dont need (for my power) 300m shafts and NASA shafts. good luck! you could use money else where than over building the tranny Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 11, 2016 Author Report Share Posted June 11, 2016 How difficult is rebuilding a craigslist th400 with spray and clutches? Any special tools needed? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
cdk 4219 Posted June 11, 2016 Report Share Posted June 11, 2016 Clutch piston tool is about it. Soft part kits are cheap, probably one of the easiest transmissions to rebuild. Only problem with a used transmission of this age is the fact that if has an inherent problem that caused it to fail, the novice builder may overlook the problem and it may cause future problems, and may destroy a rather expensive converter as well. These transmissions were solely in trucks at the end of the production, and trucks sometimes aren't taken the best care of. It is certainly one of the less expensive transmissions to work on and pretty easy to do. Quote Link to comment Share on other sites More sharing options...
cdk 4219 Posted June 11, 2016 Report Share Posted June 11, 2016 If you already have the th350, stick with that one, in a 2700# car it will probably live for quite some time if kept cool. This will save some dollars and won't pe as parasitic as the 400. An upgraded clutch pack 400 will live behind an 1100 hp 5.3 for a long time in that light of a car. You could certainly spend the money on upgrades, but I think you will be happy with the 350 you have. Take it and freshen it up with some upgraded clutch packs and put a huge cooler on it. Quote Link to comment Share on other sites More sharing options...
gbracing81 Posted June 13, 2016 Report Share Posted June 13, 2016 The only downside to the 400 is parasitic loss and weight. If it is a higher HP car and light a powerglide 2 speed will be the best bet. A new Hughes powerglide Starts at $1500, with all brand new parts. I agree with this. I have thousands of dollars in my 400. You have to replace the sprag and drum on a stock 400 to handle any power plus a stock sprag will grenade when you come out of the water box. Powerglides are relatively inexpensive to build. Basically all you need is a soft parts kit and an input shaft (to make it a turbo spline). As light as your car is the glide in my opinion is the way to go. Plus, the consistency of a two speed is deadly. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 13, 2016 Author Report Share Posted June 13, 2016 ok all, thanks for your replies. I will see how the 350 holds up first and go from there... maybe get a beat spare for mock up as the other gremlin is currently using it. Quote Link to comment Share on other sites More sharing options...
SHIEF Posted June 13, 2016 Report Share Posted June 13, 2016 Why not a power glide? Track only car? Quote Link to comment Share on other sites More sharing options...
coltboostin Posted June 13, 2016 Report Share Posted June 13, 2016 Why not a power glide? Track only car? Beat me to it. Light, small, fucking magic for ETs Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 15, 2016 Author Report Share Posted June 15, 2016 I am thinking that su the solution after the 350 blows Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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