Thread: 413 to 426

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no i just got all the info on what i gatta do , and yes my car was offered with a big block , all i gatta do is change the motor mounts and trim the cross member if im ganna run a over sized oil pan , my car had the option of a 318 ,340,360,440,400,and no hemi ,unless you wanted it to pay big extra for it

The 426 wedge (426W) was nothing more than a large-bore 413, but the maximum recommended overbore is .040" on all '58-up Mopar engines (except the Polysphere 318-based engines and supposedly Slant Sixes). Both the 413 and the 426W share rod length and main/rod journal sizing with the 440, as well as the deck height (10.72"). The vast majority of 440 speed parts will fit the 413 with the obvious exception of pistons.

Passenger-car 413s used a different lifter height/pushrod length than 1968-up 440s, but it's the same as 426W and 1966-'67 440s. It doesn't much matter, though, since as long as you swap pushrods and lifters at the same time, it's a direct swap. Virtually all aftermarket pushrods and lifters are now the '68-up style.

Early (pre-'62) 413s used an oddball 8-bolt crank with no flexplate/flywheel register (centering ring) but the common 6-bolt piece used later is a direct swap so you can use commonly-available flexplates and torque converters.

All 1968-'70 big-blocks used the famous 906 casting, even the two-barrel 383s. All used the same 2.08"/1.74" valves, too--there is no difference between HP heads and base 2v heads except the valvesprings (and in some cases, retainer style). The last year for a specific HP casting was 1967, in which the 440HP got its own specific head, the closed-chamber 915.

An even better choice is the later '70s 452 castings, which flow better than the 906 out of the box (after 1968, all Mopar B/RB heads have 2.08/1.74 valves), have the same maximum porting dimensions, and already have hardened valve seats for unleaded gas. There are millions of these sleeping under the hoods of 400 Cordobas in junkyards.

Motorhome and truck 413 engines usually have different heads than passcar engines; they have extra water jacketing around the exhaust ports and will not accept passcar headers or manifolds. They also use a unique intake, which is not a worthwhile performance piece, and many of them had 8-bolt cranks with a proprietary conveter/flywheel hub length. Plan on using only the block; virtually everything else needs to be replaced right down to the water pump housing. Put yourself way ahead of the game and just find a 440... it'll be cheaper in the long run, and have more CID in the first place.

1972 Barracudas and 'Cudas were only available with Slant Six, 318, and 340 engines... all big-blocks were discontinued after 1971 in E-bodies (Barracuda/Challenger models). No '72 anything was built with a Hemi, and less than a dozen Six Pack 440s got out (in Road Runners and Chargers only) before that plug was pulled as well.

You couldn't even get a Tilt Six E-car after '72, the '73s being 318 or 340 only and the 340 being replaced with the 360 in '74 (also, E-body production ended early that year, never to resume).

However, the E-body non-Hemi V8 K-member is the same 1970-'74 (the '70-'71 440 Six Pack models had a skid plate, but were otherwise identical). The only change necessary to bolt the big-block to a '72-up car is the motor mount brackets which bolt right to the engine lugs--the mounts themselves (the rubber parts) are the same, be it 318 or 440+6. The big-block also requires its own transmission--a SB unit won't bolt up--and the radiator probably needs to be changed or have the hose fittings moved, depending on what year water-pump housing is on your big-block. The lower hose inlet moved to the opposite (passenger) side in '73. Plan on new exhaust, as manifold outlets are located differently between big and small-block, and obviously the manifolds themselves won't interchange between engines. If your car currently has a 904 transmission, you'll need a shorter driveshaft, too, since the required 727 is consderably longer than a 904. No, Barracuda and Challenger driveshafts don't interchange--the Challenger has a 2" longer wheelbase. The 6-quart "Hemi" pan will clear any factory V8 K-member without any trimming, and don't forget to extend your distributor wiring--the big-block distributor is up front.

Hope this clears up some confusion and maybe prevents someone from buying the wrong engine.

You reading this, Psychoward and Wildfish72?

And ..... Hey, Doc! I was hoping you would check in. Thanks!

I appreciated your posting on small-block heads. I printed it off and put it with my aforementioned "files".

And thanks for bearing me out regarding engine availability for the '72 Barracudas and Challengers. I was relying on my ever deteriorating memory on that one, and I based that assertion on the fact that I bought a '70 Duster new, then a couple of years later I went back to talk to my dealer to discuss trading for a '72 440 Barracuda. They couldn't sell me one. Just as well, I guess. I went home and kept the Duster for thirteen more years.

Tell me something not engine related: Will the torsion bars in Wildfish's Barracuda be adequate? Or are they adjustable to the extent that they can accommodate a big block? I have wondered about that.

And how about his cooling system?

Your comments are appreciated.

Jim

OOPS .... I see that you addressed the radiator situation.

Jim

The torsion bars will hold; in fact lots of racers use Slant Six bars to aid in weight transfer... but I wouldn't want to be caught on a mountain road with anything less than the factory big-block bars up front on a mountain road (all E-body T-bars are the same length, shared with '66-'72 B-car bars).

Without a swaybar, I wouldn't even pull it out of my driveway.

As far as the radiator, I consider a 26" 3-row mandatory... but if you can make a big-block stay cool with a 22", good for you. Too many years in the Atlanta heat taught me that the 22" rad just won't do. My current preference is to cut the core support to accomodate a '78 360/AC truck rad, resto-correct be damned. When using the early big-block water-pump housing, moving the lower outlet is a cake-walk for any competent radiator shop.

Interesting side note on four-row radiators: According to Chrysler factory testing, the fourth row so many hold dear actually picks up heat from the first three rows, and therefore is a complete waste of time. Plus, it adds its own weight as well as that of the extra cooler.

Hey that was some good reading. Thank! I have a 197? 400 so Iam going to check the heads out. Just maybe. Thanks for all the info. It really help to find this stuff out before I go doing something stupid with the block. You guys are like wizards. Thanks alot.
Don