I need ideas???

[Uncletruck]

After buying a new Tacoma truck, my '78 LeMans has now become my official "project" car. The frame, body and paint on this car are perfect, so the project is all powertrain, that being dumping the 231 Buick V6 and metric TH200.

I have left in my arsenal an excellent shape '84 TH350C transmission that I would like to use, it has the BPO bolt pattern. I already have front springs for a V8 installed on the car to handle any sort of small block weight.

I have a few criteria:

1. Acceptable gas mileage. Not looking for 25 MPG, but less than 10 isn't going to fly with me. Would like to see around 15 MPG. Would an Olds 350 or 403 be able to give me that or near with the TH350? The car is a sedan, so I'm not going for an all out hot-rod, just decent performance. (Hey, anything should beat the 231, right?) Reliability and smooth running mean more to me than it being a ball-hauler.

2. I don't do my projects crappy or bother with crap such as well worn out $100 beater engines, just not worth the physical effort of the swap for me to do things like that. I have some money to spend for a decent engine- not a fortune, but I'd like to get something done in the $1000-1500 range. I'm aware of the list of other things I'm going to need to swap in anything other than another 231, and that list is about the same regardless of what small block I use.

3. Maybe something different?? I've been told the Pontiac 301 was a piece of crap by a few, but can anyone with experience confirm that? It's HP rating is right on par with a Chevy 305, and it would actually be a preferred swap with my transmission.

Just looking for ideas to be tossed out here, and any suggestion is helpful and welcomed 😀 This is a long-term project, probably to be done over the winter.

-UT-

 

[UnclesCamino]

Could look for a nice pontiac 326 or a 400. they were very common in the 60's and 70's that way you could keep the pontiac a pontiac. If you can find a late 60's 400 and put a nice stock rebuild in it, you would have a reliable and powerful engine. With a good set of gears and proper tuning you could pull 15-20 mpg. My brother averages 20 mpg in his 67 LeMans with a 400 and TH400 Trans and 2.41 rear. The the high torque of the motor the high gears work well.

Rob

 

[illregal82]

i would look into a chevy 1500 5.7 vortech youll get the mpg plus plenty of power

 

[SBCregal]

It'll be tough to find a vortec truck motor and all the goodies to install it for 1k-1500 bucks though. If you're looking for some fuel mileage and you're replacing the transmission anyways, find an OD transmission for it. If you run any sort of taller gear in the rear you'll see absolutely crap fuel mileage on the highway. It'll be tough to get everything you need for under 1500 bucks though without getting a used motor/trans and stuff like that. Like always, it seems the sbc is your best bang/buck option, then just bolt-on stuff when you have the cash.

 

[jerrycad472]

I have a 472 Cadillac in my Camaro. They are relatively easy to find and make a ton of torque even in stock form. Because of the torque you can run a tall gear and the mileage won't be too horrible. (Mine has a 3:73, which is more gear than it needs). Its a fairly easy swap in a G-Body and there are several sources of performance parts. The motor weighs less than a big block Chevy. The blocks have a high nickel content so even high mileage ones show little wear.

If you want to be different...

 

[85 Cutlass Brougham]

Well, the 301 is a piece of crap because of it's siamesed center exhaust ports, IIRC. It's a larger version of the "Buick" 265 that GM used for a year or 2 in G bodies. If I were going BOP, I would not run the 350's as they tend to be a little restricted due to their small bores. Go for a Pontiac 400, Buick 400 or Olds 425/455. The Olds 403 isn't too bad, but it's windowed main webs can be a weak spot if you really lean on it. I would also run a TH200 4R instead of the TH350C and run 3.23 gears with it. Oh, and of the V8 turds GM turned out in the 80's the Chevy 305 has the best aftermarket support. Unlike the Buick, it has a Iron body oil pump-the Buick and Cad I know have aluminum housings with steel gears which tend to wear out and kill bearings.The Olds 307 is not a good option either as the Olds 350/403 is the same externally and makes more power for the same money. If fuel economy is a big concern, a properly set up Quadrajet can't be beat. You may be able to find a complete 350 powered parts car or truck to strip for a few hundred bucks on a site like Craigslist.com Don't overlook full size vans as parts sources either.

 

[pose_442]

If need be, Jeg's sells an adapter plate to adapt an SBC to a BOP transmission for less than $60. Part #555-60170.