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Old 07-14-2011, 08:33 AM   #51
The Youngen
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Re: Questions about a Gas to Diesel conversion for a '72

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Originally Posted by 67_C-30 View Post
Did you get one off government liquidation?
Waiting for one to pop up on craigslist. Im hesitant about surplus because ive heard they cost up to 3-4k on average. Way over my budget. Ive seen a xouple on craigslist in my area for 1-2k running but rotted, which is fine by me. Plus, the surplus aparently take awhile with governemt paper work before it can actually be yours. And i have to have this project done by september.
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82 Chevy K20 Suburban 6.2/TH400/NP
95 Chevy 4x4 1500 Tahoe 6.5T/4L80E
04 Chevy 4x4 3500 Silverado 6.6T Duramax/Allison 1000 (work truck)
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Old 07-14-2011, 09:12 PM   #52
67_C-30
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Re: Questions about a Gas to Diesel conversion for a '72

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Originally Posted by The Youngen View Post
Waiting for one to pop up on craigslist. Im hesitant about surplus because ive heard they cost up to 3-4k on average. Way over my budget. Ive seen a xouple on craigslist in my area for 1-2k running but rotted, which is fine by me. Plus, the surplus aparently take awhile with governemt paper work before it can actually be yours. And i have to have this project done by september.
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I bought my Blazer running with 46,000 miles on GL for $1305. You can figure on a 3 month wait with GL though.
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‘72 C-10 SWB , 350 4bbl, TH350
'69 C-10 SWB , 250 L6, 3 OTT
'69 GMC C3500, dump truck, 351 V6, NP435
'84 M1009 CUCV Military Blazer

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Old 07-15-2011, 07:24 AM   #53
The Youngen
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Re: Questions about a Gas to Diesel conversion for a '72

I was thinking about putting a t5 behind the n/a 6.2. It has a 2.94 1st and a .73 od. If my math is correct, with stock tires at 28.5 inches, .73 od, 70 mph, and 3.08 in the back it is roughly around 1800 rpm which is according to dieselplace.com the rpm/mpg sweet spot. Plus, it should actually get better off the line than the turbo 400 because of the 2.94 1st vs 2.54 with 3.08. Reason im asking for someone's thoughts was because everyone has said 3.08 and a 700r4 (.7) od, will kill mpg but thats for gas, it looks to be beautiful for diesel.
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95 Chevy 4x4 1500 Tahoe 6.5T/4L80E
04 Chevy 4x4 3500 Silverado 6.6T Duramax/Allison 1000 (work truck)
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Old 07-15-2011, 07:45 AM   #54
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Re: Questions about a Gas to Diesel conversion for a '72

I haven't checked,but I figure my '85 Jimmy 6.2/700r4 came through with 3.08s. I never drove it to check mileage before going with 3/4t 4.10 axles with 35" tires. That puts my ratio at right about 3.73,based on the stock 3/4t 235/85 tires at about 31". That stuff came from my '91 Suburban 6.3/4L80E which got 22 mpg on hiway with all that. These things have more low end torque than most give credit. 1800 rpm would be a breeze to this NA motor.
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Old 07-25-2011, 09:12 PM   #55
1968CHEVYC10
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Re: Questions about a Gas to Diesel conversion for a '72

Well if you need more motivation, just took my truck on a little road trip and got 22mpg, and it even has a leaky injector.
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Old 07-25-2011, 09:55 PM   #56
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Re: Questions about a Gas to Diesel conversion for a '72

6.2/6.5s love to toast injection pumps and lift pumps. You are money ahead in the long run to go Cummins. Here is a 72 build you could look into.

http://67-72chevytrucks.com/vboard/s...d.php?t=310493
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Old 07-25-2011, 10:55 PM   #57
TrkEnvy
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Re: Questions about a Gas to Diesel conversion for a '72

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Originally Posted by ZombieWeinerDog View Post
the new ford 6.7 is made in house.

if i was doing a diesel conversion today, i would do either a 12 valve or a new 6.7 iron-graphite block thats nice and light. matched to a powerglide from a 6.0 ford, it can handle more power than the allison.(allisons are very overrated.)
Yup ford does make its new diesel. Cummins has been with dodge since 89 but it was a motor that was and still is an agricultural motor/tractor motor dropped in a truck. I love my 12 valve cummins. Has 258K miles, never had the head off and I get 21mpg hwy.. Chevy bought its duramax tech from isuzu.. And the allison is a good tranny but likes to go into 3rd gear limp mode when you add more power.
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Old 07-26-2011, 12:23 AM   #58
67_C-30
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Re: Questions about a Gas to Diesel conversion for a '72

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Originally Posted by 6lcummins View Post
6.2/6.5s love to toast injection pumps and lift pumps. You are money ahead in the long run to go Cummins. Here is a 72 build you could look into.

http://67-72chevytrucks.com/vboard/s...d.php?t=310493
The only ones that have IP trouble are the 94 - 99 6.5's with DS4 computer controlled IP's. The have a drive by wire system and the throttle is controlled by a pump mounted driver (PMD). They are troublesome, but all the 6.2's and early 6.5's mechanical IP's and are stone reliable. Cummins are great, but are no means a drop in these trucks. They need either a body lift or firewall modification to fit in a 2WD and they put a lot addition weight on 1/2 ton ball joints, wheel bearings, etc. The low RPM capability of the Cummins is going to require an OD transmission to run highway speeds as well. If you building a truck strictly for mileage, you'll never offset the cost of going with a Cummins over the 6.2, unless you already had the Cummins.
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'67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435
‘72 C-10 SWB , 350 4bbl, TH350
'69 C-10 SWB , 250 L6, 3 OTT
'69 GMC C3500, dump truck, 351 V6, NP435
'84 M1009 CUCV Military Blazer

67 C-30 Turbodiesel build thread
http://67-72chevytrucks.com/vboard/s...d.php?t=254096

My trucks
http://s226.photobucket.com/albums/d...ediafilter=all

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