I am still trying to determine what to put in my 71 challenger convertible. I bought it with a 1972 400 that needs a rebuild. Its going to have a 5 or 6 speed tranny but I don't know if I should build the 400 into a stroker motor or put in a 5.7 or 6.1 hemi from the bone yard. I know the conversion kits for the hemis have got much better/easier.

What would you do if you had the choice? I'm also assuming the prices will be somewhat similar after all is said and done, would you agree?

I would say for a daily driver that you would want to take out of town and enjoy with the top down the 5.7 hemi would be the ticket... You will get some performance, mpg and drive-ability will be allot better also..

And you can put the Hemi emblems on it...

Well the price thing could be argued either way depending on what you use and how good of deals you can get and so could HP. If you are thinking that you want to use stock heads than the 6.1 will be faster, it will make more HP OOTB and weigh a lot less, plus with a big stoker kit in the future and CNC ported stock heads it can make incredible HP, the big block will need heavily worked Victors to keep up in the HP department. Now TQ on the other hand it will be hard for the hemi to keep up as most of the stroker kits for the hemi only get up to 440 or so cubes while the 400 block can swallow over 500 cubes. To make 700 hp with a hemi you add a 440 stroker kit and port the heads, 950hp on a mopar single plane intake or XV intake and big cam and you are there, stock blocks can take it with their cross bolted mains. 700 hp in a 400 block is scarey, you need a good girdle, aluminum caps, aftermarket heads...

You will get lots of different takes on the subject but that is my

Phew, tough question of the day.......

I would go with the 400 stroker: The car is already set up for it, you can build it to any power level you want, and the maintenance is simple.

If you are going for something more modern with the 5.7/6.1 then the engine will be out-dated by the time you are done the swap. That is, the 6.4 is already on it's way out, the 5.7 has already gone through significant changes, and I'm sure Mopar is working on the final version of the Hemi; a 426/7.0 liter. To keep up with the new engines is going to be very expensive.

What is it that you want to be able to do with the car?

With a nice stroker engine which is build for torque you don't need 5 or 6 gears nor steep gears in the back.
The stock transmission or an A518 with a bigblock-bellhousing and 3.23 gears are more than enough for happy cruising.
The Hemi only adds potential 'misery' in the form of a bunch wires, injectors and computer stuff. Sure it will mostlikely get better MPG but other than that probably the only fun-factor is when you open the hood.
With a stroker motor the fun happens every time you press the gaspedal...

Stroker will be muuuch cheaper and muuuuch easier.

Well those are exactly the responses I was looking for. I am not going for 700hp, rather a fun, reliable and snappy ride. I really don't care much about mpg's as this is strictly a "fun" car, not a daily driver (except to work on all nice days, work is only a mile away from home).

So, now that I'm leaning towards the 400 stroked, tell me how you would build it.

What kit?
How many cubes?
Heads?
six pack? dual 4's? efi? single?
others?
estimated price (roughly)?

I hope this is not asking to much and I'm sure answers will be all over the place, but would be nice to get a bunch of opinions. Again, don't care about high hp, lets just build a fun motor that doesn't break the bank!

another angle, a 5.7 and 6.1 will not "sound" like a big block. I have a 6.1 in my runner and even with upgraded cam, it is not the same.

And the wiring and mods are a bit of a challenge, but do-able.

However that 6.1 does run real nice.

roll bar?

The reason I said the 5.7 was that this car is a vert.. I have never been a fan of any vert being on the race car side..

Want more hp than that stroker? Add a turbo tp the 5.7 and run away from the stroker 400. And that is easy... I am looking at a 67 fast back barracuda for a race car and it will have a turbocharged 5.7 in it.. I just do not understand why people are so afraid of wiring...

have a 512 in my Challenger... would I do it again? nope.. everything from here on will be late model stuff...

I'd go with the stroker. The 3.75 stroke 451 or 3.9 stroke 470 make great combos with decent height pistons and rod ratio for durability. Top it off with mildly ported Edelbrock or Stealth heads and a cam in the 230-240 @.050 intake range and you should have 450 to 500 torquey and streetable HP. Compression ratio in the low to mid 10's with quench should be very happy with pump gas.

Anyone else?

I can tell you from experience, that if you want to enjoy the car because it's a convertible....don't get too carried away with the motor. When I built my 71 Challenger conv. back in 92, I put a beast of a 340 six pak motor in it. Sure it ran like a gut shot cat, but it was not much fun just to ride in. I ended up taking the hot 340 out, and replacing it with a mild 360 around 94-95. It's still in there, and the car is MUCH more enjoyable without all the thumping,shaking and having to hunt race gas. If you build a stroker, build a mild 451 that you can run big block HP manifolds on, and get one of Jamie Passons new 5 spds to go behind it. Good luck

I would stroke that 400 and run some ported aluminum heads on there. Torque is king in a street car and with a stick you won't be able to get the smile off your face. As for stroker kit have a good local shop balance it so that it gets balanced correctly. You need to hook up with someone who knows how to build a stroked 400 and have them guide you through choosing the right parts based on what you want.

Yes build a 408 small block. I like the little package big bang effect. Light weight = better handling better stopping,oh and with my 422 small block 11.1 stock eddies and a hughes flat tappet hyd cam my duster was getting 20 mpg at 70mph. Keisler 5 speed and 3.23 gears helped.

I think it all boils down to, do you want to put highway miles on it, or do you want to put 1/4 miles on it? Where is your heart at with this car?

My vote would be about a 500 to 512 stroker in the 400 block. 10.5 to 1 Ported Edelbrocks (jump on one of the deals on race section) A mild hydraulic roller cam (but milder cam for sure 230/236 ish @ .050 duration.)
will make a good cruiser in a 505 will act like a 218/224 cam in a 400 cube.
5 speed and have plenty cruising fun. 750 3310 vacuum sec or an 800 edelbrock thunder series.

I'd run the 400. You own it. I'd stroke it. Had a 452 stroker with M.P. aluminum heads, 500 horse on pump gas and it's still running strong 10 years and 80k later.