View Full Version : 413 Has Potiental

02-27-2001, 07:34 PM
I purchased a 71-413 motorhome engine for very little money. The block, crank and rods are in excellent shape(odometer showed 32,000 miles) Hensley Motor Shop of Knoxville,TN-Strictly Mopars, told me that that block has thick enough walls for a 60 over bore. This would allow me to use stock bore 426 pistons. Any other helpful ideas would be a plus-yes,this engine will be used on the street-70 Barracuda, 4-speed, 323 Sure-Grip,8.75

02-27-2001, 10:52 PM
I bet those heads are wimpy. Designed for max torque. Might want to check them. No use choking a 426 wedge!

03-01-2001, 08:07 PM
the r/v heads are worthless-i want to go with a set of alum. heads-and a fuel injection sys.

03-01-2001, 08:26 PM
Hi pishta and 1970grancoupe!

I'm jumping into the fray because I am looking for all pertinant advice on rebuilding a 413 for the street (hopefully I can shoehorn it into my '48 Special Deluxe). First question to grancoupe: Are you trying to go for the 426 bore because you want to or because you have to? -Goes to a question of 413 overbore piston availability and wanting to preserve a little wall thickness for the next time around. I am having a hard time finding a source of stock overbore pistons, and am considering something like JE custom pistons. Second question goes to pishta: grancoupe said that the setup would be used on the street, so why wouldn't he want to go for max torque? Most of the dragstrip top speeds are illegal (pity the bloke whose top speed isn't), and to me, all of the fun is in blowing others doors off from zero to "35", well, OK then, "55"...or so.... Anyways, are the 2463200 heads on my 413 too restrictive to benefit from a nice porting job in order to get a balanced combination of low-end torque and mid-range horsepower for the street? If so, what do you think about a pair of 346 or 452 heads for this application? -or a pair of 516 heads? I'm only asking about the ones that are immediately available, but would welcome your ideas for the best ones to get.

Also- thought that the 413 was discontinued in the mid 60s, so how is it that the 71 motorhome came with this engine?
Thanks for your input.

03-01-2001, 08:35 PM

1970grancoupe- If you are sure that you are getting rid of the stock iron 413 heads, I would like to know which heads they are (casting numbers?) Perhaps I can make it worth your while to give them a new home, if they are a desirable type. Also: would like to hear about your approach to fuel injecting the 413. Thanks


03-01-2001, 08:49 PM
The reason for going with the 426 pistons is they are easy to find, new or used--i should say easier. wall thickness is not a threat--i hope that a future bore will not be needed--I want this engine to be a daily driver so fuel milage is a must. I hope this combo will supply that--The power i need will be enough, i think i'll be somewhere around 375 hp. the 413 was used in r/v applications until 75--hard to believe but true--now this block is not a wedge block--but it does have a steel crank and a high nickle content--this block was cast with extra thick walls for R/V's only, so overheating want be a problem. the heads are 2899943--they use a special water pump that branches of and supplies the block and heads with coolant at the same time--weird isn't it. if you think these heads might be of some use to you, i am sure we can work something out. oh yea--the torque will be there, as this engine is a tall deck

03-01-2001, 08:57 PM
the valve sizes are 1.78 int.----1.50 exh--oh yea, do you get the MOPAR MUSCLE MAG. ?--if not you should--great source of info.

03-01-2001, 09:08 PM
Jesus, those valves are on my 273!! The torque will be there, but the motor will run out of air at 3500, unless you got some major hiway gear, that cars not getting past 60 MPH ;-)

03-01-2001, 09:26 PM
that is why im not using them--i see you have a 64 cuda--i sold mine 3 years ago, it was a 273, 4-speed black on black

03-02-2001, 01:55 AM
Where are you going to find a 426 wedge piston? Nobody has made those for years. It is going to cost you more to build a 413 than it would a 440 and it will make less power since it is smaller. Find a 440 block and use the 413 crank and rods and the project will go easier. Or find a 400 block and drop that 413 crank and rods in there. That will give you a low deck 451 motor that will really rock.

03-02-2001, 06:04 AM
Use the 413 if you have it......I would suggest use '452' heads...they have hardened seats and can flow great numbers. They came on all 76-78 400 and 440's. I run '452's' on my 400. Great head. Should bolt on.

my $.02

03-02-2001, 07:40 AM
Thanks for the education folks. I see what you mean about the valve sizes; didn't know about the motorhome engines or the 943 heads. Despite their restriction, I would like to say, as an avid bone-yard scout, that big block V8 goodies of all makes are rapidly becoming harder and harder to come across in the central Ohio area. Makes me want to NOT throw away anything. It is hard to ditch a 413 complete engine in order to use the crank in my 400 block (one super engine rather than two cool engines), but I would eventually like to find the 440/451 conversion reciprocating assembly for my 400. Are 440s readily available in your parts of the country?
Also- have any of you had any experience with custom piston sets for the Bs and RBs? Any advice?
I know of a set of 452 heads and will latch on to them-thanks Jason!
Are any of you running a big block in the Aspen/Volare chassis, and if so, how well does that front end handle the weight? (better get that magazine, as you say) I'm thinking of putting the A/V front end under my '48 for disk brakes, power steering. Any thoughts?
Also-I'd like to see what all of you are doing about fuel injecting these old big blocks. Is there any success in scaling up current 5.2/5.9 liter systems? -Or are you using completely aftermarket systems? Thanks again.

03-02-2001, 07:54 AM
I am running the 400 in my Aspen and it handles great. I know alot of people who are swapping the A/V suspension ..etc on to older chassis. The nice thing is that the torsion bars are compact in the front.

I didn't even have to crank up the torsion bars any. strong suspension.

I checked my KB book and they don't sell pistons for the 413 or 426 wedge. You should make a call to JE, TRW etc and make sure you can get pistons.

Are you sure that you need to bore the 413.....have the cylinders checked for taper and if it is in spec just hone it and use the stock pistons over again.. They should be a good piston because they are made for industrial use.

You could put your money into a good cam, intake,...etc.

It is low milegae and might be better inside than you think....???


03-02-2001, 08:06 AM
Thanks Jason! I lucked into this engine and do not know anything about it except that it turns over (have started to disassemble it). It is a 1963 block with 3200 heads and a cast iron single four barrel square bore intake manifold. I think that it is very good advice to have the whole thing measured before jumping to conclusions. Wonder if it is an early enough engine to actually be 10:1 or 11:1 compression?

Great info on the front end swaps! Looks like extensive front frame horn modification would allow use of the rubber isolation blocks, or else the unit could be welded in without the blocks. Do you see either method being preferred, or are both being done? John

03-02-2001, 08:29 AM
I would use the MP solid insolators for the K-Member to frame.

On my site in the parts pages you will find the part number an a pic. Click on the suspension pic at the top of my page . (sometimes you have to close the Geocities crap first to see the pic).

Also check out the big block swap page ..I have the number for Schumacher Engine swap guys. You can used any A/V K-member and bolt any engine to that K-member using their mounts. I would suggest swapping in a v-8 K-member.


Fury Boy
03-02-2001, 06:39 PM
Why couldn't you bore it over to a 383 bore and use the stroker pistons(or do they not make them for stock bore 383s?). By the way, can a stroker piston be used in a non stroker motor( like 431 pistons in a 383 w/ stock stroke?)?

My uncle had a 413, the block was cracked, but it still could run like a bat out of hell(out of a '63 new yorker, in a '66 charger)

03-02-2001, 07:41 PM
thanks 451Boy, that is something to think about, but since i already have this block i guess i'll use it. After all it's only 14 cubes less. It is a good block. I can order the pistons from KB. Not that expensive. GO DODGE GO

03-02-2001, 07:53 PM
BBASPENSE thanks for the advice, iv'e got a set of 452 heads-if i cant find a set of alum. heads i'll go with them. MOOOOPAR!!!

03-02-2001, 08:13 PM
KB doesn't make 426 wedge pistons. Nobody makes 426W pistons anymore. The difference in cost between custom pistons for a 426W and off the shelf 440 pistons will more than pay for a 440 block. But hey, it is your money. Spend it however you want. (hopefully you aren't going to order 426 Hemi pistons for a wedge. That just won't work. KB does make 426 Hemi pistons so the only thing I can figure is that you've mixed those two things up)

03-02-2001, 09:23 PM
I have a friend with a 64 Chry 300 w/ the 413. He just did the performance work you are thinking about. Bored to 426 Bore, TRW Lightweight pistons, Stock Rods, STOCK 413 HEADS, MP Purple Cam, Original Cross Ram Mopar Intake, Comp fo 10:1. Changed to a hydraulic valvetrain. The motor is supposed to have Approx 400 HP. Still breaking the motor in as of now.

This was not a cheap build mind you but it can be done.

Note: The stock 413 cross ram setup was supposed to be a 425+hp motor.

413 dart
03-02-2001, 09:35 PM
i have a 63 413 bored 30 over so there is pistons to be had if you can't find them send me a email i will get the name from the guy who did my motor. ps i'll ask him about the 426 pistons andy

Fury Boy
03-03-2001, 12:11 AM
why not sleeve and use original pistons? I heard Maurice Petty sleeved every motor he built so he could have a rounder and more rigid cylinder.

03-03-2001, 12:15 AM
If someone can show me a part number for a 426W piston I'd love to see it. I have catalogs from the major vendors here in my office and no one lists a 426W piston anymore. They haven't been available for at least 10 years. Only 413 pistons I know of are stock replacement cast ones.

If you really insist on doing a 426W then you can use a 383 piston and use a Hemi length rod. That will get you close enough that you can zero deck it with only minor machining. Of course, Hemi rods are going to cost you at least $500. If you use a 383 piston and stock rods then you'll have about 8:1 compression.

03-03-2001, 06:44 AM
You can get parts for any engine...not all are shown in the books.

Lets take an example of what I mean. Lunati cams makes a Stock Eliminator camshaft for my 360 (.474/348 dur). It is not listed in the book but they do make it. I've talked to them and it is not a custom grind.

JE Makes stock replacement pistons for my 360 that are forged. They are for Stock/Super Stock racing. They are not listed in their books but are listed in National Dragster.

National Dragster listed Stock replacement pistons from the following manufactures for the 413.

1241 Silvolite (Keith Black)
JE 101619

For the 426 Wedge are as follows

L2185 TRW
1756P Sealed Power
2303 JE
L2184 TRW
P2520 L C&A

Give them a call with the numbers listed...they can give you a price.


Fury Boy
03-03-2001, 12:29 PM
Well, in this case, I also have a 413 block stashed away, but it is cracked, what do you guys think about sleeving it? I would also pore some of that hard blok in it. As I said before, Maurice sleeved all his engines to get a rounder whole in the piston.

03-03-2001, 02:07 PM
BBaspen, you miss the whole point. Of course you can get a custom piston made for anything. The point was that it is going to cost this guy more to get custom pistons for a 413 or a 426 than it would to just find a 440 block and use stocking pistons. The part numbers you listed are not for shelf stock pistons. They are Stock or Super Stock replacement pistons that are approved for use by NHRA. That falls into the category of custom, if they are even available anymore. The JE pistons are probably available, but most likely in the $700 range. Last time I checked, the TRW's weren't available anymore (Just for fun, I called Summit with your part numbers. Those part numbers are no good in their computer which means that they have't sold them in over 5 years).

Futhermore, I wouldn't be surprised that the numbers you listed were for a 426 max wedge. That would be the last thing this guy needs. 13.5 CR isn't going to work on the street.

03-03-2001, 03:31 PM
451BOY, you could be right when i called KB and asked about the pistons they could have got mixed up and told me the wrong info. Iwill check again. If the 426 wedge pistons prove to be a problem i will go with the stock bore, since the block is fine. the original pistons are ok, and i may use them. I would like to had a larger bore, but i can live with the stock bore. 8.5 comp. is a little low. iwould preffered 9.5--maybe i can make it by working the heads. since i'm not in a hurry to complete this project, i can explore all options. who knows, maybe even a turbo could be used. that would be something to think about. keep the ideas coming