400 stroker with 413 crank?

[Larry Petersen]

OK here goes I've got a 74 roadrunner with a 1968 400 motor out of a charger it's got a Mallory ignition and a holleyes street avenger that's about all I know about this motor it runs good and I'm assuming the internals are stock, I also have a 413 punched out .30 with flat top pistons, 906 heads, some Crane rocker shafts assembly, moly pushrods rods also crane, a comp cam with some high 5 int exhaust numbers like 580 588 but don't quote me and a forged crank that's 10 under, so my question is, being that the 400 has bigger wider beefier mains can I use this crank? I also just got a lighter set of Heads beam Corrillos and am currently looking for some pistons, and I'm crazy about the Hughes whiplash cam although it's for a lower compression engine and I'm hoping that after I get this built that it's at least 10 or 11 to 1 but I realize that can be determined by decking and shaving etc.. so all that said my car is just for the local "Stoplight 500" on Friday nights, but I'm a sore looser so whatever we come up with here has to be some serious HP, PLEASE ADVISE, thanks guys first time thread right here.....glad to be here.

 

[HT413]

Welcome aboard, Larry! As I'm sure you know, 413 crank is zact same as the 440 crank, so turn her down and stuff her in.

BUT...

Instead of having two killer big block mopar engines, you'd only have one slightly more killer more bigger block mopar engine. Maybe keep the 413 together and buy another crank for the 400/451? For maybe couple hundred bucks, you'd still have two killer mopar engines.

 

[Larry Petersen]

Lol true, I guess I could just get a crank, although I did tear the 413 down to see what I had purchased, that's how I gave up the parts list, bought it off ebay for 100.00 didn't do to bad I don't think.

 

[HT413]

You stole that for sure. Coincidentally, I just went from a 413 to a 451, though my 413 was a low compression truck motor.

I only have 100 miles on the 451 so I'm going easy, but I can tell you its worth building one. This thing goes! and I've never even opened the secondaries yet

 

[YY1]

Check your casting date on the 400.

it's NOT a 1968.

First year of 400 was 1971 in Chryslers, and 1972 everything else.

 

[66Satellite47]

YY1 is certainly correct, the 1st year for commonly available 400's was '72. '68 Chargers had 383's. The low deck 451/2 motors work great. I agree with HT413, you're probably better off buying a new 400 stroker crank and/or kit. I built 2 low decks in the '80's using the cut down 440 stock steel cranks & they still had the stock undercut rod journals ( weak spot). New aftermarket have radiused journals and usually a stronger forging alloy. Having said that, the 413 crank would work fine if it's good to start with (mag'd, crack free).

 

[Larry Petersen]

I contacted that guy I got the 400 from, it was a transplant into the 68, it's actually a 74 motor, which I guess I had forgotten about because when I described building the 74 roadrunner I told him that I thought the 400 was the biggest motor that year available with 4speed, and at the time that was my idea. Now I'm leaning more towards a bulletproof 727, I do have a question though, are the guts of the small bellhousing 727 the same as the big one? Just different case? And this car was originally a 360 car, so do I have to change the k member to accommodate the 400? I just saw on ebay a 440 crank 10 under for 150 plus freight, says steel but that don't mean forged or cast to me, ?? The 906 heads I've heard are good heads and I've heard 915 are too? Which are better? And here's the classic question that has led me down some " sorry I didn't listen" roads....cam choice, the cam that was in it seemed pretty rad to me...hang on I'm gonna go look at the numbers on it, i know it's a comp, which honestly I'm not crazy about them but....21-233-4 that's what's been hand scrawled on the end of it. Anyways I appreciate you guys giving me the input, I'm no rocket scientist and I don't know how to do the equations that gives you all the critical mass at 2750 ft elevation on a Sunday clear blues sky's in fall with six bottles of 104+ you get [?] at 60 ft blah blah bl...well you get the idea, I don't know how it all works but I sure do love it when the 5.0 stang is choking on my BFG smoke and his girlfriend ....never-ending you get my drift.

 

[66Satellite47]

The small block 727 is GENERALLY the same as BB 727's except the case. But there are a variety of internal parts variations in both BB & SB. Front band apply lever has several ratio choices, front servo has a couple different spring combinations, front drum can be 3 or 4 clutches (Hemi's had 5), planetaries both front & rear can be either 3 or 4 pinion, valve bodies have different upshift points (I'd always use an aftermarket valve body). Far as I know the K member is the same just different motor mounts. 906 & 915 (big valve) heads are the same except the 915 is closed chamber for a higher compression ratio compared to the 906. They will surely need to be rebuilt. Pocket porting on those makes much more power for very low expense. The cam is pretty big .540I & .558E lift(w/1.5 rocker) and 252I & 260E duration @ .050.