Gasser HotRod Forums banner
1 - 14 of 14 Posts

·
Registered
Joined
·
77 Posts
Discussion Starter · #1 ·
back to getting on the build. Reminder...mild performance 350...carb, cam, headers,intake. debating on what trans would be best for my application. Got a donor 700 r4...no history on it and it needs a converter. Was looking at the possibilitiy of a shift kit and maybe a brake. I see alot of turbo 350 and 400 already done from reputable people for decent prices....are the 350&400 better or easier to work with?...seems performance parts are more accessible..what do you guys think?
 

·
Administrator
Joined
·
13,411 Posts
I agree with Steve. Hard to beat a TH350/400, and for most applications the TH350 is a better choice, as it's lighter, and less HP robbed. The 700R4 will give you a lower 1st gear, and taller OD gear with a 2.75 1st, and .70 4th gear, but if you don't do much freeway driving it may not be what you need.
The cost of torque converter, and build for a 700R4 is much higher than a TH350 also, and although they can be built just as strong, it will be at a greater outlay of cash. Around my area I see some really great prices on TH350's ready to drop in. I bought my race built TH350 for my Austin off CL for $200 with a driveline tossed in.
 

·
Registered
Joined
·
44 Posts
If your going do the street strip thing,The 700r is the trans you want.
Yea, it's more expensive to have one built for your application but it's worth it.
Like others have said, the 700r4 has the low first gear for the strip and the overdrive for the street.
As for your rear diff gear you can use a 4.11 or a 4.56 and still have street manners.
_______
Laddy
 

·
Registered
Joined
·
7,423 Posts
I think you guys basically summed it all up. But I'm curious about the brake? If the car is street strip won't the brake be over the top? If big horsepower is the intension then 700 r4 might not be the best choice without spending for all the upgrades to keep it from blowing up. I think a stock 700 is good for around 400 or so horsepower. If you're running a brake then I smell big cubes and Hp. I guess all the trans mentioned above would need an upgrade in that case. As steve said just my humble opinion.
Mm
 

·
Administrator
Joined
·
13,411 Posts
I think you guys basically summed it all up. But I'm curious about the brake? If the car is street strip won't the brake be over the top?
Mm
Yes, I agree. A trans brake is not something I'd want on a mostly street trans, regardless of which trans you chose. I'd just go with the proper stall converter.
 

·
Registered
Joined
·
922 Posts
I read somewhere that a brake wasn't available for the 700R4 and that on the strip, because of the low 1st gear has a lot of RPM drop going into 2nd. I still plan to use one in my Henry J although the core I have is an early one and may not work out.
 

·
Registered
Joined
·
77 Posts
Discussion Starter · #8 ·
I'm starting to lean towards the 350...as for cost and availability. decisions...decisions
BTW...thanks guys for all the input
 

·
Registered
Joined
·
2,322 Posts
Remember the 700R4 uses a 3.06 first gear. The jump to second is huge compared to the usual auto trans. But it is not a bad trans for the street with the OD. A 2004R is a good choice with a 2.75 first and better gear spreads but thy both need good stuff added to make them stronger. Both can be built to take a strong small block with decent power. One draw back is the higher cost of torque converters for the OD transmissions. Especially if you still want the lock up feature. If OD is not a concern then go to a TH350. Strong enough for most applications. Easy inexpensive torque converters with every conceivable ratio (hell, you can buy them off the shelf at Wally-Mart, LOL) and good gear spreads. The TH400 is all the same but bigger, heavier, but much stronger even in full stock condition. A lot of times a good rebuilt TH400 with a good shift kit will handle 80 percent of all the hot cars out there.

Mark L
 

·
Registered
Joined
·
28 Posts
I run an AOD in my Morris Minor with a 400 hp small block Ford.I have a 4.11 gear and can cruise at 70 mph at 2100rpms all day long.My AOD is stock except for a shift kit and convertor.I am building a 57 Chevy shorty wagon with a 350 and will be using 700 R 4 to get the highway rpms where I want and use a 3.73 gear to try and get the front wheels up on launch.
I used a stock TH 400 with a manual valve body and a trans brake in a 10 second big block Chevelle.They are bulletproof.
A P/G with a 5800 stall and a 5.86 gear will get you launch like my old Faded Memories car.Not much for gas mileage though.
 

Attachments

·
Registered
Joined
·
2,322 Posts
I've seen TH350's take everything you could throw at them in stock/kitted form and I've seen them rebuilt with just good clutches give up with 400 hp. But with the cost of TH350's being so reasonable, you could go through a couple before matching the cost for a built trans. (if you don't mind swapping them out). Especially in a lighter smaller car where the TH350 would fit better than a TH400. I had a first year Turbo Buick Regal ('78) that I built a strong Buick 455 for and used the original high mile V6 TH350 and stock converter and it held up pretty well.

Mark L
 

·
Administrator
Joined
·
13,411 Posts
When I was racing my '71 Camaro I blew the TH350, and was going to have a local trans guy build me a TH400 to put behind the 427. He was pretty determined that I should go with a TH350 for racing, as he said I'd gain a little HP with less rotating mass, and small weight loss. I finally agreed and let him build up the TH350. I raced that trans for another 7 years, plus later another 12-13 years of street use, and it was working like new when I sold it earlier this year. I wouldn't hesitate to use a TH350 on a build, even up to around 500hp, if the guy doing the build puts all the good parts in it to make it work.
 
1 - 14 of 14 Posts
Top