Crate Hemi Conversion Help & Questions

[Carlwalski]

I am looking at buying a 426 Hemi for the 71 'Cuda (when I find it). I would go for the 528 or 472 but the 528 especially, is too much engine IMO for a street driven "daily driver". Also, for me, when people talk Hemi, nothing screams Mopar than those famous three digits - "426". I have already decided that instead of buying a Mopar block over the counter, getting it here, tearing it down, blue printing, checking and reassembling, I will get it built by Ray Barton. I have not heard a bad word about him and many seem to speak highly of him and his engines.

I have a few questions that will not only help me but also offer some others help if they decided to do the conversion. At current, the 'Cuda is/was going to be a 340ci. What parts will I need to put a Hemi in? Do the k-frames come in big and small block variety or is there also a "special" Hemi k-frame? I know I may/will need new engine mounts, I've been told Arruzza's are the way to go as Schumaker mounts have too many problems. I also know that I'll have to install a small booster and offset linkage as I have power brakes (where would I get that from?). I will run tti headers, unsure of size at the moment. Any other items or parts needed to install a 426 into a 71 Cuda? I've informed Keisler of the swap so they have made the corrections to the 5-Speed set up, so, transmission mounts and hook-up is all sorted.

Another question, what kind of block is best? Aluminium, cast iron or graphite? I would like light so I'm thinking aluminium but is there any draw back with going aluminum? I just want the best, light, good power/flow and long lasting set up. I will be running a single 4bbl carb, Mopar recommend 750cfm Holley but I may go for a 850cfm Holley or Demon. I like the look of a 2 x 4bbl set up but under a shaker hood no one will see much and a 4bbl is a much easier setup to drive and live with on a daily basis, not too mention correctly tuned is right up there with any set up.


This is Ray Barton specs for their 426 Hemi builds:

- Mopar Performance Hemi Block
- Mopar or Stage V aluminum heads (what would you choose?)
- 4340 non-twist steel crank
- 4340 steel H-bean rods
- JE, CP or Diamond pistons (what would you choose?)
- RBRE rocker system
- Moroso oil pan
- Mopar or RBRE intake manifold (what would you choose?)
- EFI or carburetors available
- Professionally assembled
- Dyno testing available


Any input and help is much appreciated.


Cheers,
Carl
NZ440R/T

[Chryco Psycho]

Alum blocks are fine , you will need an Mls head gasket like Cometic
I would use Stage V heads over the Mopar heads for sure
The RBRE intake si superior
I would use a Holley HP series 950 CFM 
 The other builder I would look at is Tim Banning @ For Hemis Only

[Carlwalski]

Thanks Neil, I've saved the build with the changes you recommended.
Yupe, I've heard of Tim and had that website already in my favorites folder.

So, you yourself would use an aluminum block? I'll be asking for a build of around 500hp so a very easy number to get. I know mag articles should be taken with a grain of salt but Mopar mag got 494hp with a carb, headers and a good tune so 500hp is basically it's stock output. What kind of weight difference would I see between the two, do you know?
Cast iron weigh about 30-40lbs more? 950!! Sounds thirsty but, ah, it's a Hemi!!

What piston brand would you choose from that selection? I'm leaning towards Diamond on brand name alone as that's tyhe only one I've heard of or that rings a bell.

Anything else I maybe missing off the top of your head?
Oh and I'm not quite sure what you mean: "you will need an Mls head gasket like Cometic"
Is that for "cosmetic" looks or is that a brand name? lol sorry.....


As always,
Ta very much.

[Chryco Psycho]

http://www.cometic.com/

I would use an alum block , I believe you lose around 100 lbs this way
 Diamond or JE are both top quality pistons

[Carlwalski]

Thanks Neil, exactly what I needed to hear.


So engine build & setup will consist of:
 
 - Mopar Performance Aluminium 426ci Hemi Block
 - Stage V aluminum heads
 - 4340 non-twist steel crank
 - 4340 steel H-bean rods
 - Diamond pistons
 - RBRE rocker system
 - Moroso oil pan
 - RBRE intake manifold
 - 950cfm Holley HP carb
 - Cometic head gaskets
 - Arruzza engine mounts
 - Install a small booster & offset linkage for power brakes
 - tti headers & exhaust with Flowmaster mufflers & electric cutouts
 - 5-Speed Keisler TK0-600 (0.82)

Now, what will I need k-frame wise? Are big block k-frame's made to take Hemis?
Also, I saw somewhere while searching that I will? need to upgrade to heavy duty torsion bars. Yes? No?

[Chryco Psycho]

The V8 K frame will take the Hemi with conversion mounts , TTi will clear
 I would go to a .96 or 1" T bar just for the handling

[Dray]

Hey NZ,

I am doing an exact same upgrade on my Challenger, but I am farther along as I will be dropping the engine in a couple of weeks.  I got my engine from Tim @ For Hemi's Only and he is a borderline hemi genius.  I highly recommend him!  Also, I am probably as close as a person can get to being a noob, so don't take my suggestions as gospel.

This is a good link to list some of the gotcha's involved with this kind of swap.  http://www.engine-swaps.com/window_Hemi_Tech_Tips.html  Key points include Power brake booster size, torsion bar, and radiator replacement <bottom outlet changes from the 340 to the hemi>.
Another good link is http://www.ttiexhaust.com/Header-214%20Hemi%205/STG5-214.htm.  Key point is the small high torque mini starter and the Schumacher Engine Mounts which will fit with your K-member the 340 is sitting on.
I suggest you stiffen the frame up with subframe connectors and torque boxes.
I believe you will likely need a bigger fuel pump.
You will have to purchase new alternator and power steering pump brackets.
If you have drum brakes you might want to think of upgrading them to disc as more power suggests needing better stopping power.
I added front and rear sway bars from Firm Feel and also upgraded the steering box <the old ones have too much play> again from Firm Feel.
You might want to look at upgrading the differential.  I went with the Truetrac to handle the added torque and upgrade to a limited slip.

That is all I can think of for now.  Good luck, it is going to be an exciting <if not a bit expensive> project.

ciao,
dray

[Carlwalski]

Thanks Neil.


Also, thanks a heap Dray. Good info, input and links. What crate have you purchased?
The classic 426? Or the new numbered 472 and 528 engines?

There a re definitely more items that need changing than I thought!
But, IMO, worth every penny for a Hemi. 


Cheers,
Carl

 

[BIGSHCLUNK]

 




'nuff said 

[Carlwalski]

Can't wait!

Have you had any issues with yours? If indeed it is a crate. Who built yours or did you get a MP Engine and tear and inspect? Have you ever driven in an original Hemi, if so, what is the sound comparison. I've seen numorous posts/comments etc while searching saying there is absolutely no difference in sound.

[Dray]

Hey NZ,

I bought the 426.  For a street application I don't really see a point in going to to the 472 or 528.  With mild upgrades to my build Tim was able to squeeze 698hp  out of the 426.  I found it interesting that he was able to gain 50 more hp using an EFI package over his tweaked carb build.  Lots more $$$ for the EFI though.  I posted some pics of my engine in another thread if you are interested in taking a look.  Cheers!

http://www.cuda-challenger.com/cc/index.php?topic=32116.0

ciao,
dray

[Carlwalski]

Hey NZ,

I bought the 426.  For a street application I don't really see a point in going to to the 472 or 528.  With mild upgrades to my build Tim was able to squeeze 698hp  out of the 426.  I found it interesting that he was able to gain 50 more hp using an EFI package over his tweaked carb build.  Lots more $$$ for the EFI though.  I posted some pics of my engine in another thread if you are interested in taking a look.  Cheers!

http://www.cuda-challenger.com/cc/index.php?topic=32116.0

ciao,
dray

Thanks mate, sure looks like a drop dead gorgeous engine indeed!!! That's what I thought, overkill for a street car (the 472/528) but you ended up with more power than a stock 528, some 80 hp more! What transmission are you going to run behind it?

[67Vette427]

NZ is joining the big boy hall of fame   

In my 70 Challenger I used the 472 crate engine. Easy install with the Schumacher mounts but I used Hooker Super comp headers and they were a pain. The 472 is a great running motor and no problems. I did that swap in 2003. The only problem was at idle, the brakes would lose vacuum because of the cam. It was an auto car and was very streetable.

In the 71 Cuda I went a little different. Both cars used the original k members and Schumacher mounts.  I used the real nice TTI headers on the Cuda and the engine is a 528 CI that I built from the start. The only thing aluminum is the heads (mopar perf). I used the .96 torsion bars in both cars. Going with the aluminum heads I think I actually cut weight off the 440's that were in there before. The car is in the paint shop now being painted black and getting the shaker hood fit on it.

I decided to build the hemi because I already had most the parts like the intake, oil pump, pan, distributor, water pump and so on. Plus I know how it was done. I still spent 14k or so just on the motor.

The cast blocks are what I used. I couldn't see the extra $$ for the aluminum.

[Carlwalski]

NZ is joining the big boy hall of fame   

In my 70 Challenger I used the 472 crate engine. Easy install with the Schumacher mounts but I used Hooker Super comp headers and they were a pain. The 472 is a great running motor and no problems. I did that swap in 2003. The only problem was at idle, the brakes would lose vacuum because of the cam. It was an auto car and was very streetable.

In the 71 Cuda I went a little different. Both cars used the original k members and Schumacher mounts.  I used the real nice TTI headers on the Cuda and the engine is a 528 CI that I built from the start. The only thing aluminum is the heads (mopar perf). I used the .96 torsion bars in both cars. Going with the aluminum heads I think I actually cut weight off the 440's that were in there before. The car is in the paint shop now being painted black and getting the shaker hood fit on it.

I decided to build the hemi because I already had most the parts like the intake, oil pump, pan, distributor, water pump and so on. Plus I know how it was done. I still spent 14k or so just on the motor.

The cast blocks are what I used. I couldn't see the extra $ for the aluminum.

Thanks 67Vette! Sounds like we're going to be twins as the only colour I will paint mine, is the blackest of blackest blacks. It will be triple black with billboards in flat black and cop rims, 315 at the back is the aim. What transmission are you running and what hp/T did you build your car to be? Mine will be basically like below, can't wait!!!! Mine will also be the 528 with possibly Stage V heads and hopefully EFI. Do they make the 426, 472 and 528 in aluminum or only the 540 900hp engines? You'd think they would. I will be running  an aluminum to shave even more weight off the car/front end if they make them that way. I'll be running a Keisler behind it too.

[67Vette427]

I'm still running the Rally wheels but my brother is trying to talk me into the steel wheels and dog dish caps. They look pretty mean like that especially in black. That's a good picture you found. I'm using the OD trans until it blows up if it ever does and the maybe a Keisler and a Strange Dana further down the road. The nice thing about the OD is the first gear is lower than the standard 833 and it makes starts a little better. The vette has a built 502 ci and it tends to surge after start in first so you need to put the clutch back in if you're going to slow. I could put lower gears in but its already at 3k @65 mph. With the OD I have the best of both worlds for less $$ and I can leave the 3:55's alone.

The Cuda may be out of the paint shop next month so I'll get some shots of it to post. I added a skid plate and put the 26" radiator support back in it. The car was hit years ago and somebody put in a 22" support from another car. It always ran warm with the 383 so there was no doubt it would run hot with the Hemi. It will have the flat black billboards " HEMI " and I may go with some 18" polished Americans or the similar style wheels from Stockton wheel. They're pretty nice. Check out their website if you haven't already.