Will I hate my V8 conversion keeping the 4 speed? (1 Viewer)

[alex e]

My mechanic suggested I get an NV4500 for overall driveability and gas economy(??!!) over keeping my stock 4 speed. 5 speed will be better........Of course I already invested in the Downey adapter setup anticipating the 4 speed install behind my 350 TBI. Apart from keeping the RPMs down, what am I missing out on by keeping the 4 speed? I will not drive the 40 on the highway at all. Just putting around town for fun and hunting out of it some. Mostly just a sunny day vehicle for short jaunts, etc.

V8 guys weigh in here please.....THANKS!

 

[lucky 13]

how much do you drive your fj-40 cuase my SM-465 is great and icould only imagine the NV-4500 being slightly better of a daily driver. and theV8 is great.

 

[vk7ybi]

The lower first gear seems like the only thing of any real advantage..

 

[Bret]

Tire size can give you "rubber overdrive" that will help with cruising RPM's too. DD with the 4spd tranny was no problem. You may find you want lower gearing if you do rocks, etc.

I've had 35's/37/s with my 4spd and I like it on the road.

 

[mminter1973]

4spd and a v8 is all you need. Use tire size and gearing to adjust to where you personally like it.

 

[dgangle]

From what you say it sounds like you may want to pass on the NV unless you got a money tree and/or you just want it. I have driven V8-powered 40's since the early 1980's all with the stock 4 speed. They are very durable, shift like butter and are already paid for since the trucks came with it.

Like previously said, you may want to adjust your OD with tire size and/or ring & pinion ratios. I run 33's with 3:70's & it'll cruise 80MPH on the highway without breaking a sweat.

It all comes down to money. How much do you want to spend? I have read the NV takes over $100 just to fill the darn thing up with synthetic oil. I could buy 2 good used 4 speeds for that.

 

[cruiser_guy]

If you don't drive on the highway with the '40 ask the mechanic when you'll use 5th??

 

[dgangle]

double post

https://forum.ih8mud.com/40-55-series-tech/239236-will-i-hate-my-v8-conversion-keeping-4-speed.html

 

[zuluzeugma]

Get bigger tires, thats all the OD you need.

 

[mtthmpsn]

I drove my buddy's 69 FJ with a 3-SPEED and v8 and I felt like I was in a more comfortable RPM range on the highway than with my '77 4-speed 2F engine. Of course he has 33s and have 31s, but I would think a 4-speed with the v8 would be just about perfect.

 

[UNO_RACING]

I have an NV4500 with a heavely modified V8 and love it. Its got a great low first gear that will climb just about anything.

The HWY driving is great as the truck RPMs at about 2,200 at 65-70MPH...with good driving behavior. I have 35x15x12.5 tires, 4.11s with an Aubrun locker.

 

[missipboy]

from your description of what you will be using it for, i would leave the 4 speed. less money, time and modifications.

 

[65-fj45]

I have both, 350, nv4500 and a 350, sm420 4spd. The nv4500 is a lot better all the way around, mine has the 6.34 first gear so i'm not as low as the 420 but it works great. With that said, if your not going to use the 40 on the highway stay with the 4spd, you already have the parts and you'll never tell the differance.

 

[nspctr1]

NO, buy the 4500 and take out the crappy old 4 spd. I'm coming to Big D for the State Fair and I'll be glad to haul off the remnants....

 

[K2KK]

I've got the 4 speed with the 3 speed transfer and I love it. I also have 5.29 too so my top speed is around 60-65 comfortably. That's running at about 3000 rpms. The whol thing is turning 35 x 13.50's. I have no complaints. Keep the 4 and save your money...

 

[Tankota]

Don't bother with the nv4500. Really expensive and not worth in imo. I actually liked my stock 4spd with v8...except in really tight sections on trails. That's why I did the sm465 swap. I don't miss a 4speed on the street...my sm465 is really like a 3spd on the street(less shifting is a bonus) cause you never use 1st gear on the street.

If you could find a toyota with a granny low that'd be nice...might even work with your adapter (H41?)



edit: the time I could see a nv4500 being nice would be if you drove your rig long distances on the freeway/highway to go wheeling. btw, you'd be surprised how many friends of mine have blown out nv4500s...but thats in towing rigs

 

[Mark W]

Your mechanic is spending your money for you... a good bit of it... on something that you do not need.... if you want a lower first gear go with an SM465... you will not use 5th around town and on the trail.


Mark...

 

[Brian in Oregon]

I was not particularly thrilled with the low end response with a Holley carb on my 350. Once I went to a QuadraJet, I had much more low end control and power.

I do wish I had a 5-speed. I'm tempted to get aToyota Aussie 5-speed and install it, since the only thing not stock with my drive train is the 350. That would certainly be a help on the freeway. Gas mileage at 55 mph isn't bad, but 60 to 65 it starts really dropping, and at 70 mph it goes from bad to worse.

 

[65swb45]

x8 on keeping the Toyota 4 speed. For a DD that doesn't see much low-speed rock-type wheeling, the stock trans is THE MOST COMFORTABLE trans option out there. Best street manners of ANY manual 4speed truck transmission.

Best

Mark A.

 

[nspctr1]

You guys aren't helping my case any. Ditch the 4 spd. it's old, tired and wants a new home.....