Well big brother and I have been kicking around some ideas for our 1970 Cutlass S

1. Folks here have said it costs about the same to rebuild a 455 as it does a 350. Car currently had a 350 in it.

2. Looking for around 400 to 450 horse power . Do able .

3. Transmission . . Still in the barn, but I would guess a TH 350 in it. Looking at OD transmission options. OK guy's be nice. 200r4 (I know) or a 700r4 . 4l60 non E transmission don't seem to exist.

4, Gear ratio. Well. Maybe a 355:1 or 377:1. Going to do a 12 bolt, not looking to do a 9" ford like we thought . Not sure if it is a 10 bolt or not. Disc brakes maybe

5. Not sure if it has disc brakes on the front or not If not, we are looking to put disc brakes on it.

5. WHEEL AND Tires . We wanted to put Crager. SO on it, but it seems like I can't find those. 15". 7" in the front . 8 " to 10 " in the rear.

I know... too many questions . Driver 60 miles MWF. each week 180 miles, plus some side trips. Mostly highway, but a little in town too.

We know it will cost $$ not $$$ or $$$$. But this will be our last car that we do.

Thanks Ya'll

 

Ok., I made a few boo boo's. 373:1 gear ratio. Posi. Unit of some kind . I have looked around and it seems that SS-1 are available in repop's.

Those will work too. We are old Pontiac guys, and have ran many of the Rally II wheels. My 65 Tempest . But that's A whole nother. Story.

 

Just my opinion, but with 3.73's you will want overdrive. If you are rebuilding from scratch go with a 455 if you are able. My personal recommendation would be to find a lower mileage 2wd 4l80e and throw a transgo HD2 shift kit in it and get an adaptor and a decent converter. This trans will require a controller at about $700 but will be the best bet to hold up to a long life behind a torquy 455.

 

AND you will have to egg out the hump as that 4l80e is HUGE and will not fit the normal floorpan.

 

The 4L60 (without the "E") is just a 700R4. GM changed naming terminology in the 1990s. The TH400 became the 3L80.

 

The floor pan mod is what concerns me. Some YouTube guys have a channel (yes I know) series where they do car builds. One is a LSX into a 68 Cutlass Kicker build. V8TV I think.. Years ago GM made a standalone Overdrive Transmission controller in a 89-92 6.2L diesel in a Van... Yes I was looking to put one in something with a diesel engine. and did.. off topic.

what about a 4l65e or a 4l70e or a 4l75e.? I am sure a lot of tranny humps have been beat on, hacked on too. Me included. But I as 35 years younger and had a better equipped shop. I don't have a problem using a TH350 or TH400 but I would have to go with a 3.08:1 or a 3.42:1 rear gearing.

No way am I going to spend $3K on a gear vendors OD unit on a street driven car... I have run TH400 and TH350 behind 454 based engines in early Camaro's in drag race only bracket cars. for years.. But the major reher-morrison big block Summit Bracket Racing Division Champion uses a power glide. no brainer Still a lot of research to do and thanks to you all it will be .a little easier...

Yes fresh build. I need to find a core engine yet.

 

The 4L70E other than a 5 pinion planet is still a nothing special transmission. They had 3/4 clutch pack failures right to the end of production. The 2004R is a direct swap for a TH350, just move the cross member to the TH400 position. Either way it also needs about 2 grand in the parts to live and many experts say if built right will survive better than the 700R4/4L60/65/70E. Why not contact Cutlassefi and do a stroker 350? He did a mild 422ci with 9 to 1 compression pulling 18" of vacuum with a 219/227 roller cam, over 400 hp and over 500 ft/lbs of torque. His 4" stroker crank is lighter and way stronger than a 330 forged crank, let alone a 455 crank. Plus stronger rods and light with a super modern 1mm ring pack forged pistons, makes parts that will out last the block in strength. The heads just had 2"/1.625" valves with the bowls opened. A core 455 is $400 to $1000 here, goes a good way to doing the stroker.

 

I currently have a built 4l70e in my cutlass. I had it built by a very reputable shop to take a ton of abuse and have over $2500 in it and the converter. It fit in the tunnnel just fine with my LS swap, but if i had it all to do over i wouldnt use any auto other than a 4l80e (to be honest i would have gone t56 if not for the wife, but she lets me spend the money without asking for anything more than to be allowed to drive once in a while and wont learn manual). For what i paid i could have had an indestructible transmission instead of one i still feel anxious every time i beat on it. A few whacks with a hammer will make one fit in an A body.

 

Well put, the 4L80E is the only "E" transmission worth building that has a hope of fitting and living behind big power.

 

I would keep the 350 engine and go with 3.42 gears, if not equipped with A/C, otherwise 3.23 gears, along with 15 inch wheels & TH350 transmission. Just my opinion.

 

How much work on the tunnel, BFH, does it take?
Most likely to have the engine, transmission, driveline done in a friends shop.

 

The back of the bellhousing and back of the trans case areas should be the only places that gives you any trouble. A-body cars have a fairly generous tunnel. Plenty of LS guys running them without cutting the tunnel and we have to push the engine and trans about an inch further back than stock for oil pan clearance.

 

with a LSx swap? Then it would seem like a 4l80e might be a wee bit easier with a olds engine

 

Should have clarified. My car is LS swapped. Yes, there will be more room with an olds engine.

 

OK. we have decided on a 455 stroker with a 4l80e. 500 HP area. 4:11 to 1 rear gears.
We be jammin

 

That will be a nice mild engine being a stroker. That combo will make huge torque, unless you plan on 1/4 mile times as your main goal, go with less gear. Even with a 275/60R15 tire, you will turn 2200+ RPM at 60 mph and 2600 RPM at 70 mph, 3000 RPM at 80. A 3.42, 3.55 or 3.73 might be more highway friendly, it will drop 300 RPM on the highway with a 3.73. I use this calculator, it assumes a lock up torque converter running locked up. A non lock up adds another 250 to 300 RPM on the highway. Just put .75 in place of the .67 the 2004R uses.
http://tech.oldsgmail.com/axle_RPM.php

 

4l80e is the way we are going to go. most likely 4:11 to 1 gears. Not a daily driver, but we will go some places in it. Cruse around Texas on a long weekend. 255/R15 tires on the rear.

 

Does it have the stock rear end? It is a 8.5" type "O" 12 bolt cover rear, plenty strong on street tires and 3.90 gears are available for it and has 28 spline BOLT IN axles with new ones available from Moser. The 70 can also use better 71/72 factory axles with an aftermarket posi. The posi available for it are modified Ford 8.8" carriers.