[HemiQuad]

I am working on a plan to replace the 5.7 Hemi with the following components.

6.1L shortblock
210 camshaft
5.7 CNC heads
LX car 5.7 intake and front cover assembly

Has anyone considered this combination, and if so what were your thoughts regarding this setup?

 

[hemi1569]

It would be cheaper to just have your 5.7 bored. A 6.1 shortblock is big bucks

 

[HemiQuad]

I am not worried about cheap, this way I get to keep the 5.7 as a backup.

 

[sawcut64]

Man if you're going with a 6.1 block you may as well just swap the heads and intake. Contact Beast2 he has done this swap on his truck, and sells most of the stuff you'll need.

 

[HemiQuad]

Well I was concerned about the headers and the 6.1 heads. Not absolutely sure if they would bolt up or not. Now if I was to go the route of the heads and intake, then instead of purchasing the shortblock, Mopar Supercenter has brand new complete production 6.1 engines as well as the short blocks.

From what I have heard from some of the best cylinder head guys in the country, the 6.1 heads are lazy until you get up to around 426 cubic inches. So for my application, I am leaning towards the 5.7 setup, as the heads flow velocity is very good, and the car intake produces loads of torque. Couple that up with the 6.1 shortblock, and I think I might just have a winning combination.

 

[sawcut64]

A stock 6.1 motor makes 425HP and 420TQ....nothing lazy about that. Really talk to Beast2 he owns the Hemi Shop and has done a bunch of what you're thinking about doing.

 

[HemiQuad]

Looking into some comparisons of the 2 engines, I am specifically checking out the bore and compression ratios. As the 6.1 has a larger bore, and higher compression ratio, but they both share the same stroke. I know putting 6.1 heads on a 5.7 raises the compression ratio into the 11's. I am thinking with the 5.7 heads I will still be below the 10 mark, offering me the ability to go forced induction later on and pull more boost. Correct me if I am wrong, as the newer engines are not something I have messed with much. I was proficient with some of the older small blocks, but they didn't have computer systems driving them. I admit, my experience with computer controlled engines is very minimal, but at least I am willing to learn. I am really kind of thinking that the current computer in the truck may be able to handle the 6.1 shorblock, but I doubt it would handle the 6.1 long block.

Below are some specifications regarding the 2 engines for reference

6.1L ENGINE

Engine Type 90° V-8 OHV
Displacement 6.1 Liters 370 ( Cubic Inches)
Bore 103 mm (4.055 in.)
Stroke 90.9 mm (3.58 in.)
Compression Ratio 10.3:1
Firing Order 1-8-4-3-6-5-7-2
Cylinder Block Cast Iron
Cylinder Head Aluminum
Crankshaft Forged Steel
Camshaft Hollow Assembled Camshaft
Pistons Aluminum Alloy
Connecting Rods Powdered Metal

5.7L ENGINE

Engine Type 90° V-8 OHV
Displacement 5.7 Liters 345 ( Cubic Inches)
Bore 99.5 mm (3.91 in.)
Stroke 90.9 mm (3.58 in.)
Compression Ratio 9.6:1
Max. Variation Between Cylinders 25%
Firing Order 1-8-4-3-6-5-7-2
Cylinder Block Cast Iron
Cylinder Head Aluminum
Crankshaft Nodular Iron
Camshaft Hollow Assembled Camshaft
Pistons Aluminum Alloy
Connecting Rods Powdered Metal

 

[sawcut64]

Beast2 has transplanted a complete 6.1 motor in his truck and made the most dyno proven power N/A to date that I know of. But whatever you decide to do, I'm sure it will be a learning experience that we can all benefit from....so go for it!!!

 

[hemidup]

Rule #1, Don't bore the 5.7 out to the 6.1, 4.055" bore. The 5.7 heads will work on the 6.1. That's what I have on my setup. I would keep the truck intake manifold for now, until the aftermarket one shows up in the near future. The 210 or 260 cam should work fine.

 

[HemiQuad]

hemidup, please tell me more about your engine and mods.
I was thinking about the 260 or 268 camshaft, but not real sure on what tuning problems I would run into. I am really glad to hear someone else is running the 6.1 shortblock, now I don't feel like a stranger in uncharted territories.

 

[SRT10KLLR]

They 6.1 cam is not hollow like the 5.7 one. I beleive it is a solid peice of billet.

I too have a 6.1 with 5.7 heads and intake.

BTW, You can have a sheetmetal intake made right now like the one below but it would cost about 2-3K.

 

[daytona1191]

thanks looks fnn sweet i wish i was rich

 

[hemidup]

HemiQuad, I have a 6.1 block with an offset ground 6.1 crankshaft stroked to a 6.4. Stock bore with 8.6:1 Ross pistons and Eagle rods. Stock 6.1, AB camshaft with ported and polished, 84 cc closed chamber, 5.7 heads with Ferrea 2.08" int and 1.62" ex valves. The complete engine assemly and block was then cryo treated to relieve any undo stress. The heads are real ''torquee'' and have very good throttle response. I plan on slipping in the Comp 260 later this season. We have been testing and designing new heads for both the 5.7 and 6.1 and also noticed the lazy intake port velocity of the stock 6.1 head compared to the 5.7. However, it's a great port design if you can increase the air speed which we are working on now. A new aftermarket intake should show up soon.

 

[HemiQuad]

hemidup, thank you for the detailed response regarding your build up. Sounds like a really sweet setup you got there. How are you tuning that setup if you don't mind me asking? With my lack of knowledge in these computer controlled engines, I was thinking of trying to maximize what the stock PCM can handle with maybe just a superchips or other downloader. So this brings me back to the question about the 6.1 shortblock with a slightly stouter camshaft than the 6.1. Would the factory PCM and maybe superchips offer me the option to utilize the 6.1 shortblock and 5.7 CNC heads with a camshaft and the LX 5.7 car intake?

I think it would be cool to be able to use the LX 5.7 engine cover, get it painted to match my custom paint job as well. Should also offer me loads more torque, and hopefully alot more throttle response. At least that is what I am hoping for.

Any insight on the future intakes that may be available?
If so, and want to keep private, PM me about it, I would really like to know more regarding this.

 

[hemi1569]

The 6.1 cam ac grind, does that make most of its power over 5000rpms? And is it worthwhile to rev to 6000 with this cam? Or is it flat at that rpm?

 

[Beast2]

There are stories that a couple of companies are working on an intake for the HEMI right now but no solid production dates or any other data out there yet. You asked a ton of questions, I will try and hit most of them.

Yes your stock PCM will run a Stock 6.1 long block no problem. I've done it (twice).

I made more RWHP with PORTED 6.1 heads on my motor than I did with PORTED 5.7 heads. So much for the lazy theory.

If you want a cam bigger than the stock 6.1 cam you will probably need a controller like the ARC1 or SMT6.

Jerry tunes his with the SMT6. I was using one of those with the 6.1 & custom cam and will probably use it with my new motor (414 cubic inch bored and stroked 6.1).

You should take a good look at the car timing cover. It will take a lot of fabrication to make it work in a truck. ALL of the accessories are different, and the upper hose exits on the wrong side. We have a complete car set up we are going to use on another project. (68 Cuda)

The 5.7 and 6.1 use identical header flanges, minus EGR. The EGR port is partially machined into the 6.1 head but must be completed. Your headers may require some grinding to match the 6.1 exhaust port, but nothing too bad. You may also have to trim the 5.7 exhaust gaskets.

I am using the 6.1 intake with our custom 6.1 intake kit for the trucks, and will until something better somes along. The plastic 5.7 intake does not work with our 6.1 kit and there is no clearance for the EGR either.

Also unless you have a 6.1 short block already, good luck locating one for less than 3 grand. For that kind of money I can make a 5.7 into a 6.1 with all forged internals and have some change left over.

 

[Beast2]

All of my 6.1 cammed combos were still making power at 6300 on the dyno. I would have to check my charts to see where the most power was at.

 

[hemidup]

Beast, I was talking about the lazy intake port velocity on a stock 6.1 head. A stock 6.1 head, definatly needs some tender loving care. Don't know what the engineers from DC were thinking when they designed that port.

 

[Beast2]

They were thinking you needed something else to work on Jerry! LOL

I know the velocity is a little slower than the 5.7, I think the increased compression helped the power numbers a good bit.

I am going back with the stock 5.7 block (with custom toner ring), 6.1 cam, ported 6.1 heads, and 5.7 intake combo and then to the 6.1 intake for a dyno comparo soon. I really liked that combo before too. It will be cool to see how it compares to the 5.7 block/head combo I have now.

 

[hemidup]

Scott, Wait until you and Stu get a hold of the new CNC ported 6.1 heads with the 2.25" and the 1.75" exh valves. You'll have to bolt them on your truck to finish out the R&D. I'm working with Stu right now to see if the intake valves will clear your pistons. These should be done by Christmas. Have you been a good boy this year?