Swaping 305 TPI to 350 TPI
Thread Starter
Junior Member
Joined: Nov 2015
Posts: 7
Likes: 0
From: Winnipeg, MB
Car: 1987 Iroc-Z
Engine: 350 tpi
Transmission: 5 speed std
Axle/Gears: 3:73
Swaping 305 TPI to 350 TPI
I am swaping a tired 305 TPI to a 350 TPI soon. Before I start, I currently have a stock 5-speed manual transmission. Will this tranny be able withstand the change to a 350? I don't plan on going crazy HP wise with the 350. Only shooting for about 330-350 HP. I am on somewhat of a budget. If it will not work, can I do some mods to the current tranny or will I need a completely different one?
Senior Member
iTrader: (1)
Joined: Dec 2009
Posts: 627
Likes: 1
From: Waxahachie Texas
Car: 88 IROC Z/28-under re-construction
Engine: 5.7 Tuned Port
Transmission: It's in there....
Axle/Gears: 9 bolt Borg-Warner
Re: Swaping 305 TPI to 350 TPI
Oh it will work for a bit then it will grenade the one time your rough with her. T-56 and be done
Supreme Member
Joined: Nov 2009
Posts: 1,255
Likes: 54
From: Lincoln, NE.
Car: '87 IROC
Engine: 5.7 Vortec w/ factory TPI
Transmission: WC T-5
Axle/Gears: 3.45 Posi
Re: Swaping 305 TPI to 350 TPI
Your T5 will bolt up to a 350 with no issues at all, but depending on which T5 you have (standard or world class) you might have to change it out. A standard T5 Should handle up to 250-300ft/lb of torque and a WC maybe 350ft/lb.
If you have the trans already pulled, or feel like climbing under the car, check out the ID tag and google the number to see what year and version you have. It will be a 13-52-xxx number. It will be on a metal tag and if the tag is gone then you can look at the side of the case. If the number is 13-52-065-913 you have a non world class trans. If the number is 13-52-065-914 you have a world class trans. If my memory serves me correctly GM started using the World class T5s in '86 and if you have one then you should be fine. The world class T5s had a stronger case and could accept more power.
I am currently doing the same swap in my '87 IROC and found out my trans was out of an '85 and wasn't a WC. I happen to be lucky and have a buddy that had a WC trans out of an '88 Camaro (Tag #13-52-176). I was super happy when I found out it had been rebuilt by G-Force, so I should be good to about 500ft/lb.
Now with all of the being said it really just depends on your driving style, weight of the car, and how sticky your tires are. I have seen guys put 500hp through a non-wc and never have an issue and I've seen stock cars blow out their factory WC transmissions. I don't plan on drag racing my car so I'm not worried at all.
This is where I get my tag info from... http://www.britishv8.org/articles/bo...t5-id-tags.htm
If you have the trans already pulled, or feel like climbing under the car, check out the ID tag and google the number to see what year and version you have. It will be a 13-52-xxx number. It will be on a metal tag and if the tag is gone then you can look at the side of the case. If the number is 13-52-065-913 you have a non world class trans. If the number is 13-52-065-914 you have a world class trans. If my memory serves me correctly GM started using the World class T5s in '86 and if you have one then you should be fine. The world class T5s had a stronger case and could accept more power.
I am currently doing the same swap in my '87 IROC and found out my trans was out of an '85 and wasn't a WC. I happen to be lucky and have a buddy that had a WC trans out of an '88 Camaro (Tag #13-52-176). I was super happy when I found out it had been rebuilt by G-Force, so I should be good to about 500ft/lb.
Now with all of the being said it really just depends on your driving style, weight of the car, and how sticky your tires are. I have seen guys put 500hp through a non-wc and never have an issue and I've seen stock cars blow out their factory WC transmissions. I don't plan on drag racing my car so I'm not worried at all.
This is where I get my tag info from... http://www.britishv8.org/articles/bo...t5-id-tags.htm
Thread
Thread Starter
Forum
Replies
Last Post
JayBoCC2
Engine/Drivetrain/Suspension Parts for Sale
11
Mar 2, 2019 02:33 AM