As discussed above, the diffence is compression ratio (different pistons) and Valve timing (different cams) other than that mechanicly all the same. Like Frank was saying the ECU's are most likely programmed differently thus ignition timing would not be the same.

You could use the heads just swap over the Montero Cams.

I gotta quit posting before my AM coffee kicks in <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> And, for some reason, Frank's post just decrypted itself to me <img src="/forums/images/graemlins/smile.gif" alt="" /> Sorry, for the redundant question. I'm apparently working to much <img src="/forums/images/graemlins/baby.gif" alt="" /> *smacks self in forehead*

Yea, I think I have the answer to most of what I originally wanted to kow but it just opened up a can of worms of more questions. Its amazing how little info is out there on thes engines even though they are in so many vehicles. Still trying to figure out if the Diamante 6g72 is an interference engine. I found one site that says it is but I cant trust the info because they also have the Montero SOHC listed as interference and the 6g74 3.5 DOHC as non-interference LOL..Maybe the Mopar guys might know for sure.

The Diamante is 10:1 CR. To me, that says interference potential. This is from an on-line reference:





EEK6g72 pages

The Gates catalog says it's not an interference engine:

Gates Catalog

Frank

Hi Guys,
I have been out of town splish splashing around up in the Adirondacks.

There are three main differences tween the RWD and FWD Diamante SOHC 12v engines.

The car cams are 4 degrees longer duration, minor amount but quite welcome at road speeds. The compression as noted is higher. And the big difference is in the intake manifold.
The car engine has more power everywhere in it's powerband, I expect much of the upper and mid power is lost in the conversion since the truck intake manifold is restrictive.
I have no information about the mapping in the ECU but the car engines do have a knock sensor and this allows the ECU to have a learn capability. This is a nice feature since it allows you to run the grade of fuel of your choice. I run 87 Octane in most all my engines with no issues.
To me swapping a car engine into the trucks is a great and simple improvement for overall driveability. I expect there should be an improvement in economy with the higher compression as well.

Charlie, this thread has me wondering if I should install the car cams in my blower engine.... with the MS ECU, I can give the engine whatever spark timing it wants and certainly don't have to worry about a restrictive intake. <img src="/forums/images/graemlins/wink.gif" alt="" />

Do you know if the 8.9:1 CR 3000GT/Stealth SOHC 12v cams are the same as the 10:1 Diamante SOHC 12v cams?

Frank

I did some more comparison, but can't find the valve timing specs for the 8.9:1 CR 3000GT SOHC 12v:

Montero/Raider
Compression Ratio = 8.9
Valve timing
intake open... 19* BTDC
close..........59* ABDC

exhaust open...59* BBDC
close..........19* ATDC

Diamante
Compression ratio = 10.0:1
Valve timing
intake open....16* BTDC
close..........66* ABDC

exhaust open...56* BBDC
close..........26* ATDC

Frank

EDITED LINK
1991 Stealth Technical Information Manual
Presented by Jeff Lucius



One of the rarest books concerning the Dodge Stealth (and Mitsubishi 3000GT) is the 1991 Stealth Technical Information Manual (TIM). This manual was prepared by Chrysler (part number 81-699-0114) as an introduction to the specifications, features, construction, and function for this new (at the time) Mitsubishi-built Dodge high peformance car. I am not aware of a Mitsubishi version of this manual. The Stealth TIM depends partly on information available in the 1990 Laser/Talon TIM (for the 4G63 engine) and on technical information for the 6G72 SOHC engine installed in a multitude of Chrysler cars since 1988. Each of the 283 manual pages is presented as a 730 x 1000-pixel GIF image that varies in storage size from 7 to 54 KB. Total disk storage is about 7.6 MB.

http://www.stealth316.com/2-stim.htm


page 9-2 says it is the same as "Ram Raider" and Ram 50.
12 valve 6g72 all have the same valve timing. ?

I cant find any 10:1 SOHC 12v