Hey guys, i couldnt find any thread about this so i thought id start one.

I purchased a 1973 olds 455/TH400 out of a delta 88. Its going into my 1988 cutlass. Im wondering about the exhaust. Will the stock 455 manifolds fit? I dont really want to spend big money on hooker headers and im looking for a budget solution. This is not a race car, just a tire peelin street car. It does not need to make 400hp. I am pretty new to all this, im not a professional mechanic. Explain it to me like im 5 haha.

 

I moved your thread to the builds and projects forum. Is the T400 a long or short tail shaft?

 

I think your gbody will require trans crossmember mods to use 455 manifolds, but I think you’ll have steering shaft clearance under the hood.
Good luck!

 

It depends on which 455 manifolds you have. W/Z or X/Z will work. Others, not so much. The TH400 from that Delta will be a long tail. You really want a short tail in that car. You'll need a new driveshaft. A 200-4R crossmember will also work for a TH400, but you'll need aftermarket or have to modify a stocker to clear dual exhausts. If you were thinking about just using the trans in that G-body, well, don't. You'll have clearance problems from the valve cover to the HVAC box. People have notched the HVAC box and fiberglassed the hole. Note that the 307 valve covers are slightly smaller than the 455 valve covers and will bolt up. Get a high torque starter for the 455, don't try to use the weakling 307 starter.

 

Thank you!

I dont know but im guessing long, its pretty damn long compared to a th350 i have on the shelf

 

All 1965-1976 Olds full size cars used long tail transmissions. If it came from the same Delta as the 455, it's a long tail, either an OK or an OR code on the tag.

 

i am fully prepared to put in a new driveshaft. I was planning on it anyway to get something stronger and have a machine shop i know modify a straonger one to length for me. I work for a crane/truck company and the owner is family so i have full access to the mechnical bay, cranes for hoists, heavy duty tools and some help from the mechanics that ive made friends with.
i have the 200-4r trans currently so i do have that cross member but ive heard you can get a dual hump cross member from summit for dual exhaust if i want. Notching the hvac box and putting in some fiberglass doesnt sound too scary. Id prefer not to cannibalize the 307 as id like to sell it with the 200-4r to recoup some costs.
Ill have to check which manifolds i have. the engine came with all accessories, starter, pulleys and belts etc. Am i to understand that the only issue with the long tail is that i need a new driveshaft?

 

IIRC the long tail may not have a speedo drive ?

I have a th350 (short tail) behind my 455, Its about the same length as the 200r4 so same driveshaft. but i think you have to move the cross member

 

I installed a 455 in my cutlass with very few issues and no major mods... Trans used was a modified 200-4R with no mods to the cross member... Exhaust was comprised of W/Z manifolds with 70/72 Cutlass/442 front pipes and an eight inch extension was added to connect to stock G-Body dual exhaust mufflers and tail pipes... The left pipe is a little lower then the right to clear the cross member since it was not modified, but it does not hit and there is clearance... To clear the AC box, I used 1973 valve covers and no mod was necessary...

 

Sorry, that is not correct. The trans length has nothing to do with the mount location. The 200-4R and the TH400 use the same mount location, so same crossmember. Also, the G-body cars are not like the earlier ones. You cannot just slide the crosmember back - there's nothing to bolt it to. The G-body crossmembers are not straight, they are angled. The TH200/TH350 crossmember is different from the 200-4R/TH400 crossmember. Yes, you can get an aftermarket dual exhaust crossmember from the usual sources.

The long tail TH400 results in a shorter driveshaft, which may cause excessive u-joint angles. Keep in mind that the G-body is only a 108" wheelbase to start with. A-body cars used a 112" to 121" wheelbase, depending on year and model. Assuming this TH400 DID come from a 1973 Delta (still no confirmation of that, by the way...), it at least has a speedo drive feature. The 1965-1970 full size cars did not have this since the speedo was driven from the left front wheel, and no you can't easily retrofit one to those transmissions since the case isn't machined for it.

 

I have done many 455 G body swaps, they are pretty easy if you plan ahead.

Before doing anything, look at the transmission case. As Joe mentioned, many big cars had a speedometer driven of the front wheel. The case has no provision for a speedometer. If you want a speedometer, either find a short shaft transmission, or plan on some machine work.

The transmission could be converted to a short shaft model. All that is needed is a short output shaft a d extension housing. The transmission needs to be torn down completely to swap the parts.

I have always used manifolds, headers are kinda of a pain in the *** on these cars unless you spend the big buck. The Hooker headers have one tube that wraps around the frame. You said your wanting a strong cruiser, the stock manifolds are probably the best compromise.

Your going to need a aftermarket crossmember, or fabricate your own. I have seen people cut and hack a stock crossmember, depends on your fabrication skills.

I have always used stock valve covers. They are a tight fit on the passenger side, but they do clear. If you plan to keep the A/C, your going to need to do some minor modifications to the front compressor mounting bracket. Don’t sell the stock compressor a d mounting brackets, you will need them.

 

^^^THIS. Here's a photo of the mod required to the 307 compressor bracket to accommodate the taller deck height of the 455. On the other side you just need a 1" spacer between the alternator and power steering pump brackets, and a longer bolt to match.

 

My 80 cutlass has the short tailshaft turbo 400 with a gforce crossmember and built to length driveshaft.it’s a nice setup with tons of room for exhaust routing .I went with the Thornton shorties which had zero issues installing . They are well made but not much better performance wise that the wz manifolds .I retained my original ac box but using the taller cheapy chrome valve covers it was a very tight fit. Not to mention the struggle messing with #8 spark plug and wire . I’ve since modified my box ( so much better but no a/c ). The 455 torque will also be hard on a factory 7.5 gbody rear , so some mods in that area may be in your future . Good luck with your build up you will love it when it’s finished

 

Okay so im an idiot and am finding out all kinds of things i didnt think about. I may have to live without a speedo for a while. I had no idea that those cars used front wheel driven speedometers. Is there any other way around this short of a full transmission tear down?

 

A GPS speedometer.

 

Going to bump this thread because my 455 is just about ready to go in. I have read these forums extensively to gain information (thanks, Joe and all). I am down to a couple of things:
bracketry: I have the stock brackets and pulleys that came with the toro motor I got. They are big, bulky accessories; can I find a set from 307 and just bolt in?
hood: using the edelbrock aluminum intake, and have not figured out the carb yet. If I use a low-profile air cleaner, I will still clear?
shifter - my 79 Cutlass has a column shifter. The bracket at the end of my shifter cable in no way meshes with what's on the short tail 400. Is there a bracket I can bolt onto the 400 that will accept my cable?

Thanks!
Tom

 

The easiest set of brackets is to modify the 307 brackets. The alternator bracket requires a 1" spacer where it bolts to the PS pump bracket to account for the taller deck height of the BBO. Similarly the A/C compressor bracket needs extensions welded on.

 

Picture is the best I could do so far to have clearance to close my factory hood . I used the toro drop base air cleaner and had to modify it . I only have a 2 inch air filter . I am using a Quadra-jet . I’ve tried some other configurations but no luck as of yet. I also used all the toro brackets and pulleys that came with the engine with no issues.

 

Thanks, Jeff, I guess I have to find one of those bases. Yours looks awesome!

 

Joe, thank you, as always. The pictures are helpful

 

My ‘78 Cutlass came with a 305 from factory. My question is concerning the AC. Can I make the log style ac compressor on the 455 work in my car’s system or is there a better route to go?

 

Great pic! Always makes things easier to understand for us new people.

Can you please share more about the drop base? Manufacturer, etc?

Looks like you retained the A/C box and indicated "I’ve since modified my box ( so much better but no a/c )." What was involved?

 

that drop base is from a factory 1974 olds toronado I cut the center section out in order to use a two inch air cleaner . I believe some of the factory corvette air cleaners might work as well they have a pretty good drop to them and for over a quadrajet.I cut away the section of the ac box and removed the condenser then made a plate to cover the hole and actually retained my heat . That gave me much needed clearance for the valve covers .

 

Interesting. Didn't even think about Corvette parts but makes sense. Thanks again and for quick response.

 

Got a quick question regarding putting an Olds 455 in my 83 Cutlass. What's the work around for the clearance issues with the valve cover. I want to use my AC and don't want to delete it. Thanks

 

I'm not sure how intrusive it is, with a 455 but I modified the heater box in my 85 Bonneville when I did the Series II swap. Sweatshirt fleece and fiberglass resin works well.

 

Thanks, it seems like I might have to do that.

 

The pic i posted was with the taller chrome valve covers ,ive since put on the factory ones and made the clearance better .im using the comp cams roller rocker arms and no issues there. Good luck with your project