How to test 5.7 hemi?

[Joe Dokes]

Fuel Injection vs. Carb.

If you buy everything new. The cost of a carbureted hemi is about the same as running fuel injection:

Mod Man Intake 400.00
650 CFM Holley 400.00 to 600.00 depending upon version
Hemi 6 Ignition Controller 475.00
Wiring Ignitions Wiring Harness 186.00

Total 1461.00 to 1661.00 + Tax Shipping + Fuel System

For 400 bucks more I'd go Hot Wire. Or you could do Megasquirt for the same or less.

I have a 2006 SRT8 computer sitting on the shelf (No VIN#), I'd be willing to sell.

Sharpen your pencil and do the math of all your different options. This swap isn't cheap or easy. (If it were it wouldn't be any fun.) The people who have the most success are those who spend A LOT OF TIME planning.

Give Matt Cramer a call at DIY Autotune and talk to him about MS3 on a hemi.

Best of Luck,

Regards,

Joe Dokes

 

[kb67mopar]

Pull the oil pan and valve covers and look for where the damage occurred to start and then go from there. The most common things I have seen in failed Hemi's (from reading forums) has been either a dropped valve/valve seat or a broken rod for whatever reason.

That engine you have looks like an older truck engine since its has the metal covers and older style coil, those early engines (03) had a few valve spring issues on the exhaust side.

Just an fyi with the wiring harness stuff, if you find a used computer hotwireauto will tune it for you for 250 (in my case he did it more cheaply since I had wiring done)

If you run a manual transmission you can get away with a more simple wiring harness and it probably wouldn't be that terrible to create from an old truck harness. If I hadn't found the deal I did on my harness I would have gone that route.

 

[Uhcoog1]

Thanks. I was unaware of that. I think I'm just gonna tear it down and build it.
I am even considering going the carb route versus fuel injection. I want the FI but the computer and wiring are becoming to expensive and difficult.
Just trying to find out what kinda performance loss the carb has over FI setup

I haven't seen EFI vs Carb on a new hemi, but the tests done on the ls1's indicate that the carb makes more top end power than the EFI. Granted, that was a FAST 102 vs a good carb intake.

In the hemi world, dyno's have been run indicating certain carb intakes (XV) give up a lot (30-40 fwhp) down low under ~4000 RPM. That particular intake didn't catch up until maybe 6000. I'm sure there are other options that fare better.

If you want a wild cam (significant overlap), you'll arguably be better off with a Carb.

 

[lxmodguy]

If you want a wild cam (significant overlap), you'll arguably be better off with a Carb.

That is completely false. You don't have a fraction of the control over the motor with a carb that you do with the efi.

 

[67Dart273]

In the hemi world, dyno's have been run indicating certain carb intakes (XV) give up a lot (30-40 fwhp) down low under ~4000 RPM. That particular intake didn't catch up until maybe 6000. I'm sure there are other options that fare better.

If you want a wild cam (significant overlap), you'll arguably be better off with a Carb.

This also might be that a carb intake for a gen III hemi has not had the sometimes years of development that other engines enjoy