Need honest opinions on a build

[qkcuda]

As background I had the original 516 heads on my 361 rebuilt, installed an Edelbrock Performer Plus cam, Performer manifold and 625 street demon carb. I am running factory A/C, stock exhaust manifolds, 2 1/4 dual exhaust, a stock converter and 2.94 gears, all of this wrapped up in 4000 pounds of 1966 Charger. I have tuned it so that it cruises very well, has decent passing power, gets good mileage, doesn't use any oil, and runs on regular gas. I am however and old drag racer and love designing and building engines, and would like more low end torque. I need honest opinions on whether I should leave things as they are or build a new short block. The factory air makes it a pain to work around.

 

[Kern Dog]

Find a 400 block and build it to look stock like your 361.

 

[qkcuda]

Here is what I am thinking about. Buy a 440 source 3.75 stroke crank, reuse the stock rods, .055 overbore with forged Icon FHR pistons, (for a Pontiac) . The cam, heads , and the rest of the drivetrain would remain the same. It would end up as a low deck 413. What do I gain? A little over 50 cubic inches, and a lot more low end torque. Is it worth it? Did I mention the factory A/C is a pain to work around?

 

[qkcuda]

I have access to a 400 block. I could build the same cubic inches using my original 361 forged crank with KB pistons. Would the smaller bore, longer stroke engine make more torque?

Find a 400 block and build it to look stock like your 361.

 

[Dave6T4]

You could build torque by putting a longer stroke RB crankshaft in your 361, along with an RV-type camshaft. You will likely have trouble finding pistons for this. Or, just put your original 361 aside, and build a mild 440. Easy 400 horses, plus 500 ft. lb. torque.

 

[Kern Dog]

That 361 is saddled with the tiny bore.
A 400 with a 3.75" stroke 440 crank is a proven torque mill and at 451 cubes, it is 90 more than you have now. You can build a set of 452 or 906 heads or even better, 440 source aluminum ones painted engine color for the stock look.

 

[eldubb440]

leave the 361 alone, you can put it in some other cruiser

 

[Dave6T4]

Here is what I am thinking about. Buy a 440 source 3.75 stroke crank, reuse the stock rods, .055 overbore with forged Icon FHR pistons, (for a Pontiac) . The cam, heads , and the rest of the drivetrain would remain the same. It would end up as a low deck 413. What do I gain? A little over 50 cubic inches, and a lot more low end torque. Is it worth it? Did I mention the factory A/C is a pain to work around?

You could do the same thing with the 400 block, and end up with a low deck 444, and pass it off as your old 361. Clean up the block with a .030" overbore, and you are at 450" .

 

[qkcuda]

I have previously built a 415 HP 450 TQ stock stroke 400, and a 500 stroker with close to 600 HP and over 600 TQ. I am trying to find a balance between power and driveability, while not going overboard. I also want to stick with the low block because of the factory air bracketry. Using the 361 block, and building a 413 appeals to my nostalgic side. I learned to drive in my Dad's 1964 New Yorker 413.

 

[Runcharger]

Small cubes. Leave it as-is, pull it, seal it up and cover it up in the corner of the shop. Build a 400 based 470. Honestly it will probably be the same cost as the small bore saddled 361. Heck, even a stock stroke 400 would be a better choice with the better breathing available with the larger bore.

 

[qkcuda]

I appreciate all of the responses. Nobody is saying close the hood and leave it alone, but then again, everyone here likes more power too.

 

[ruffcut]

I built a 512 using a 400 block for my Roadrunner. Looks like a 383. No one know the difference. ruffcut

 

[RemCharger]

Agree with the comments, leave the 361 alone and build 400 based
451- good
470- gooder
500- goodest.
Same cost , choose your favorite level of goodness.

 

[qkcuda]

Realistically the cam, heads and exhaust will be the limiting factors, along with wanting to continue to use a stock converter and 2.94 gears. Those items are locked in. I am just after more low end torque to get the heavy car moving. With the small heads, I don't think the bore size will become a limiting factor.

 

[RemCharger]

In the end Chrysler ditched everything except the biggest bores. Progress.

 

[Kern Dog]

Swap in a 170 slant six.

 

[eldubb440]

4:56's with an overdrive

 

[qkcuda]

Okay, you guys made me rethink my plans. As tempting as the 170 slant was, I just made a deal on a complete 400 from a friend. Apparently it was a 29,000 mile motor that developed a knock. We will see once I get it home and tear it apart. Something for me to do this winter! The bonus is the car will not be out of commission while I build the new motor.

 

[lewtot184]

Heavy car, smallish engine, tall gear with air; it's just what it is. Ĺeave it alone and enjoy it or jump thru the new build hoops.

 

[Curiousyellow71]

You really can't beat cubic inches for what you want to do. IMO the 361 always gives up to much displacement, unless your using it for class racing where small cubes give a competive edge. There are some 516 heads that flow better then others, but I would not use 516s on a stroker unless I had NO choice. 400 is a good start. One of our most efficient combos was 4.25 stroke, stock intake, MP .484 cam, 1 3/4 headers, pocket ported 452s w stock valves. It would get in the low 20s for mpg w 3.23s and run low 13s @108 spinning and back pedaling. Bracket racing I could put a fender on cars running low 12s. Stall doesnt much matter unless you have traction. We ran a 2200 out of a truck.