Howdy everyone,

I'm building a '72 Demon street machine which right now is just a body shell on a rotisserie. The car was originally a low-optioned /6 automatic and it spent all of its life in Texas.

What I want is a fun street/strip car and I plan on installing a T56 Tremec 6-speed manual transmission, a Strange S-60 rear end, Cragar wheels, disc brakes all around and I anticipate keeping the interior pretty much stock (including a bench seat) except for a Peak Dashes gauge cluster. I'll likely use both manual steering and brakes and an aftermarket A/C. I also want the car to have a slight sleeper look so I may keep the stock flat hood for now.

I don't have any of the drivetrain or suspension parts so I'm building it completely from the shell.

I am, however, having a hard time deciding what engine to put in the car. I'm looking for good power which also doesn't have fuel economy constantly in the single digits, which the overdrive in the Tremec will help prevent. To put it in perspective, my daily driver is a TJ Jeep Wrangler which, at its worst, will give me 12 mpg in the city and I'm okay with that. I want to drive the Demon semi-regularly, i.e. a couple of times during the week and on weekends, so I don't want a radical engine that gives five mpg even on the highway.

Here's what engines I've been contemplating so far:

1) Mild 440 - I already have a complete '75 440 I pulled out of a junk yard this summer for around $300. It will need a complete rebuild including a forged crank. If I rebuild it for the Demon, I'd probably keep it slightly hotter than the stock 440 Magnum, for example with a Lunati 60302 or 60303 cam, Stealth Heads, good compression, etc. Combined with the T56, I figured it'd be a good balance between low-end torque and decent gas mileage when cruising.

My major concern, however, is the fitment of a RB block in the A-body, mainly with spark plug access and general maintenance. Like I said, I'm going with manual steering and brakes so I'm not concerned with that and I'll also use Schumacher or TTi headers, but I am worried about if I'll have room for an A/C compressor, which is a necessity here in Texas.

I am drawn to using a big block because I like having the distributor in the front.

If I use the 440, I'll use aluminum parts where I can to save weight.

2) 400 Big Block, stock stroke - This is an interesting combo because most people just build a 451, but I think a 400 would be capable of good power plus a B block would give slightly more room under the hood. Is spark plug access and what not a notable difference between the B block and the RB block in an A-body? Also, even with the stock short stroke, can I get plenty of torque out of it? On another forum I saw a '72 Dart with a 400 which was running high 11s. I'm pretty sure I can get off-the-shelf pistons for it that give a good compression ratio.

3) 408 - If I build a 408 stroker, I'd build it to about the same power level as a mild 440, but will it have enough torque at a lower RPM comparatively? I would have more room in the engine bay but I prefer having the distributor in the front of the car plus simply the look of a big block when you open the hood.

4) 383 - Same advantages as the 400, but I'm wondering if I can build it for plenty of torque. I am running an A-body, however, which helps. A 383 would seem like a great balance between power, fuel efficiency (especially with two overdrive gears in the T56) and the look of a big block under the hood.

5) 451 - Also considered a 451 stroker, but it may lean more towards performance over everything else plus I already have a 440. Would the extra room in the engine bay a B block provides be worth the added expense of building a stroker motor over a 440? I know the 451 revs faster but I'm not building a drag car so a lot of its advantages are moot for my goals.

I also toyed around with the idea of a 360 or a carbed 5.9, but I do lean towards a big block.

What do you all think? I'd like to hear your comments and suggestions. Thanks!