454 460 horsepower swap into a 1987 V10 with 700r4

[Shoote]

I am swapping the original 350 ( TBI ) for a 454 ( carb ) that is mild with about 460 horsepower. The trans is a 700r4. Tires are 33" and the cam is 501 intake/510 exhaust 216 intake/228 exhaust duration @ .050-122 LSA. I believe the gear ratio is stock, probable a 308 maybe?? Any suggestions on what stall lockup converter to use with this set up? Any advice is appreciated!!

 

[NickTransmissions]

I am swapping the original 350 ( TBI ) for a 454 ( carb ) that is mild with about 460 horsepower. The trans is a 700r4. Tires are 33" and the cam is 501 intake/510 exhaust 216 intake/228 exhaust duration @ .050-122 LSA. I believe the gear ratio is stock, probable a 308 maybe?? Any suggestions on what stall lockup converter to use with this set up? Any advice is appreciated!!

Contact your cam manufacturer, let them know the particulars of your vehicle including final drive ratio, engine, transmission, Y,M,M vehicle and they will give you a stall speed range for that cam grind in context with the rest of your powertrain/drivetrain.

Also, no need to write everything in bold font. Reads like you're screaming/shouting...

 

[75gmck25]

That’s a lot of horsepower for a 700R4 unless it’s been beefed up quite a bit. You need to talk to a transmission builder.

I am surprised you could get a 454/460 HP with that mild cam unless it also has other significant upgrades. Are you sure of the engine specs?

I would also look for gears or axle to swap, and get something like a 3.73 ratio. 3.08 gears and overdrive will hardly be turning any rpm on the highway.

 

[NickTransmissions]

That’s a lot of horsepower for a 700R4 unless it’s been beefed up quite a bit. You need to talk to a transmission builder.

I am surprised you could get a 454/460 HP with that mild cam unless it also has other significant upgrades. Are you sure of the engine specs?

I would also look for gears or axle to swap, and get something like a 3.73 ratio. 3.08 gears and overdrive will hardly be turning any rpm on the highway.

Ive built plenty of 700R4s behind big blocks making around that much torque/power but he's near the upper limit, beyond which you could spend an infinite amount of money and still break the transmission in short order...a few main things have to be card for, hard part wise and hydraulics but, if upgraded properly, the 700R4/4L60E family can handle up to around 650 horsepower though you're about equal in terms of trade offs at least if comparing a 4L80E swap which is what I recommend for most builds 600+ hp/torque.

And you're correct about the final drive...He should install a 3.73 gear set. That plus a good stall for his cam grind/application, etc would be a great combo...His existing ratio was hidden in plain sight in all that bold font text lol.

 

[Shoote]

I thank you for the input. Why does the gear ratio matter? The factory gear ratio works fine with a 350 so why would a 454 be different?

I did not realize the font was bold when I typed it on my phone. I thought capital letters denoted yelling in text not font. So nice of you to point that out.

 

[SquareRoot]

Big block, 460 hp, 3:08 gears and a 700r4....

 

[mrdap]

TH400 or 4L80E

 

[NickTransmissions]

I thank you for the input. Why does the gear ratio matter? The factory gear ratio works fine with a 350 so why would a 454 be different?

I did not realize the font was bold when I typed it on my phone. I thought capital letters denoted yelling in text not font. So nice of you to point that out.

You're welcome on both counts.

Final drive ratio has nothing to do with what engine is installed but has everything to do with its relationship with the overdrive gear ratio in the transmission. Too tall a final drive will bog the engine when in 4th and TCC lock up while providing insufficient line rise rate when you go to accelerate in 4th gear in an attempt to downshift. This insufficient line rise rate stresses the 2-4 band and 3-4 clutch pack because there's insufficient hydraulic clamping pressure on both applied elements (servo piston and 3-4 clutch apply piston) to keep the band and 3-4 clutch pack firmly holding...So what usually happens is you have 4-3 'cut loose' where you have a false neutral condition upon heavy to WOT acceleration while in 4th attempting to kick down back to third.

Many aren't aware of this when doing OD transmission swaps into older vehicles with tall final drive gears that were designed/engineered to work with three-speed direct drive auto transmissions or four-speed direct drive manual transmissions (Muncies, BWs, etc). So they burn up the OD clutch and/or band in the swapped overdrive automatic transmission (700R4, 200-4R, and so forth).

 

[Shoote]

I am not changing the transmission only the engine is being changed.

 

[Rusty Nail]

Or so you say...

 

[Rusty Nail]

What was the question?

Oh yeah - stall speed. Are you making a race truck or is this your daily lol?? The brakes won't hold much.
Maybe some pix could help.Are you sure you even really  have a squarebody truck, Junior?

 

[NickTransmissions]

I am not changing the transmission only the engine is being changed.

If you have 33" tires you will prob want a deeper final drive ratio but that's assuming you actually have 3.08 and not 3.23 or 3.42. 3.73 would be ideal, IMO.

Please quote my post or mention me if you want me to respond to any of your replies. I dont get notifications unless someone quotes or mentions me.

 

[Shoote]

Thank you for the advice. I think you are correct. I also have a 1985 GMC 2 wheel drive I changed the 305 to 502. I had the 700r4 beefed up and did have to change the rear gears to 373 from 273. 22 years later and it still drives great with 32 inch tires it turns about 2200 at 65mph. I need to figure out what the gear ratio is on the 1987 4x4 and make a decision based on that information. It's been so long ago I forgot about changing the gear ratio in the rear end. Thanks Nick Transmissions!!

 

[NickTransmissions]

Thank you for the advice. I think you are correct. I also have a 1985 GMC 2 wheel drive I changed the 305 to 502. I had the 700r4 beefed up and did have to change the rear gears to 373 from 273. 22 years later and it still drives great with 32 inch tires it turns about 2200 at 65mph. I need to figure out what the gear ratio is on the 1987 4x4 and make a decision based on that information. It's been so long ago I forgot about changing the gear ratio in the rear end. Thanks Nick Transmissions!!

You're welcome, man. I'm sure that 502 sounds beastly!

 

[JBswth]

That’s a lot of horsepower for a 700R4 unless it’s been beefed up quite a bit. You need to talk to a transmission builder.

I am surprised you could get a 454/460 HP with that mild cam unless it also has other significant upgrades. Are you sure of the engine specs?

I would also look for gears or axle to swap, and get something like a 3.73 ratio. 3.08 gears and overdrive will hardly be turning any rpm on the highway.

I don't think a 700R4 can handle the torque that a 454 will produce. I would get a Turbo 400 instead. And with tires that big, you are going to have to use much deeper gearing. Maybe around 4:10, or else 1st gear will be much too tall.

Mike