Chevy conversion questions??

City
Halifax
State
UK
#1
I have searched the internet but cannot find a proper answer to this question as opinions seem to vary.
The new Scrambler i have purchased has a Chevy straight 6 in it that the previous owner put in place of the 2.5 Iron Duke i am assuming they used the 2.5s bellhousing when installing the straight 6 but do not know for sure, is there any way of telling???.
Gear box is the T176 which has a Ford pattern i understand!!!

Will a V8 or V6 Chevy bolt straight up to the bellhousing or is there more involved in this conversion than meets the eye?. Some seem to say the larger clutch plate wont fit in the housing and a new bellhousing would be needed and some seem to say yes it will, i am now just very confused :crazy:

20150129_153644.jpg
 

Ron84cj

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Bend
State
WI
#2
Sorry for the late response. A chevy v8 will bolt in place of a 62 up chevy straight 6. But not all chevy v6s will bolt right in. The chevy 4.3L will, the 2.8, 3.1 etc was not the same pattern. I'm sure that's where a lot of people get confused. I just did this swap in my buddies 66 Chevelle. As far as clutch size. It depends on if it was out of a truck or car. The trucks used a larger clutch. You will know right away if it doesn't fit when you try to assemble it. The clutch for a car is a little smaller (like a Firebird). What year chevy engine you put in also makes a difference(pre 86 or 87 up.) If you have a particular setup in mind I would be more than happy to answer any additional questions you may have. :wave:
 

CBRogers

Perpetual Parts Collector
LIFETIME
CJ-8.com Member
City
Yorktown
State
Va
#3
There is a bunch of info on this type of swap out there but here is an excerpt from this thread.

http://www.cj-8.com/forum/showthread.php?8868-chevy-350-conversion&highlight=350 swap




Unless you're making your own mounts, use the mounts made by M.O.R.E. They are The best, bar none...and they can be a bolt on, if you want.

Here's a list I copied from one of my earlier posts...


Ok...I grabbed my folder of notes...(I wish I was that neat...I copied the numbers off the box labels I stuck on the garage wall)! So...here goes. If you have any q's, let me know. Oh, and to let you know what I started with, it was an 82 GM "Iron Duke" 151 4 cylinder, with a T-176 trans, and a 4" lift.

1. Motor mounts- M.O.R.E
2. Headers- Hedman "Tight Tubes"
3. Radiator- from Tellico 4X4, about $189.95, works fine.
4. Hoses- Napa # 7470 and #7575. Not sure which is for the top or the bottom, I do remember the bottom had to be trimmed at one end.
5. Power steering hoses- I had Napa make up some compression Fitting splices to fit two hoses together. Works great.
6. I used a stock long water pump with a stock fan clutch, stock fan, and a Commando V-8 shroud. (a cj V-8 shroud should work too).
7. The stock bellhousing fit the Chev 350 motor, find an "iron duke" bellhousing for your swap.
8. Use a 153 tooth flywheel, a diaphragm pressure plate Napa CA1897, and a Napa RCF 556 10.5" disc. This is the combo for the T-176. Use the stock 82 T-176 throwout bearing, and keep the stock hydraulic clutch setup. You will need to file one of the slave cylinder mounting bolts to clear the oil filter, you'll see...
9. The trans mount is attached to a plate which cantalievers the mount backwards. Reverse this setup, you will need to drill new holes in the skid, but they will be on a level area. Again, you'll see.
10.The rear driveshaft is ok with a 4" lift. The front is extended a little too long, but I haven't overflexed it to pull out (yet).
11.The GM hei distributor needs a strong 12v power feed, one of the existing wires will work. Also the temp and oil pressure senders on my 350 were compatible with the stock gauges.
12.I got rid of all the other wires...I hate clutter. Oh, and I used the stock "iron duke" starter...and it cranks the 350 with authority. The GM starter has a built in solenoid, so you can loose the external starter relay and associated wiring. Positive cable to the batt terminal on the starter and the "hot in start" wire to the ign terminal on the starter.
13.I used a stock mechanical GM fuel pump, and capped the tank vent hose.
14.For a daily driver manual trans, the T-176 trans is ok...a little slow between shifts, the 350 builds revs fast. I like the T-176 mostly because I cant justify the $$$ for a NV4500. I am going to a 700R4, I want overdrive with my new 4.56 gears, and my scrambler is a daily driver (50 mi/day) and I am getting too old getting tired of shifting. The TH350 is a great trans too...but with either auto there are going to be clearance problems along the right side of the pan.
15.Everything else seemed to fall into place...but every swap is different. Good Luck!

Ok...that's probably my longest post. I may have to print this out and keep a copy for future reference...but if you have any questions, need any advice, or need pictures of a certain area- let me know!!!

Hope this helps!!!

Last edited by Randyzzz; 10-30-2004 at 12:50 AM.





Basically the Chevy v-8 has had the same bell housing pattern from the early Gen -1's up through the current LS style Gen-IV engines. The 4.3l Chevy V-6 is basically a SBC with a set of middle cylinders removed and therefore shares the same bell housing. The Smaller v-6's that Chevy used are different. Also the Iron Duke 4cyl that Jeep used was the same bell housing as the SBC. So the old Iron duke bell housings that were drilled with the Ford style transmission pattern on the Back ie T-176 will fit any of the SBC engine style rear mounts. Also the T-176 trans pattern is the same as a T-18 so you can go to a granny gear transmission if you wanted. Also some of the T-4/5 Iron Duke bell housings have a cast in dimple where you can drill it out for a Ford pattern transmission.


There is a lot of info there to use but if you can get or have one of these you can even sub in a late model 4.8/5.3/6.0 GM engine.


Carl
 
City
Halifax
State
UK
#4
Thank you guys, i never expected a parts list as well!
Thing is i can buy an entire running Astrovan or Blazer for half the price i can buy a V8 for and i noticed the Astrovan has hydroboost on the brakes from stock as well :)
Just need to get the blue one finished now......
 

Randyzzz

Scrambler Junkie
LIFETIME
CJ-8.com Member
SOA Member
City
Redmond
State
OR
#5
My list makes another appearance! :thumbsup: One edit- The cheapy conversion radiator wouldn't cool well under load, and eventually started leaking. I replaced it with a Northern aluminum radiator, works great.
 
City
Halifax
State
UK
#6
Well 4 years later i now have a Vortec V6 from a 2000 year Blazer sat on the workshop floor and the related 4L60E and the wrong drop fancy NP electronic transfer box sat next to it.

In 2 minds now whether to just buy an adaptor to mate the 4L60E to the D300 and make life easier for wiring and maybe life less stressful on the drive train or stick with plan A and bolt it up to the T176 as originally intended.

I have a question for those who have ever done the V8/V6 swap to a manual first though.
The flexplate measures over 14" so i guess i need a flywheel and clutch from a manual blazer of the same year if i wish to go manual and not a smaller 10.5" clutch as mentioned above or will that just cause me clearance issues in the bellhousing?.
Or is the 153 tooth flywheel mentioned in Randyzzz list a special buy from somewhere?
 

Ron84cj

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Bend
State
WI
#7
I believe the 4.3 commonly got the 168 tooth flywheel. But a 153 tooth flywheel with the 10 1/2 in. clutch is way more common. Just get one from an 87 to 92 305 firebird. I can't tell on my phone but do you currently have a SBC bellhousing bolted on to the T176? If not you will need obviously the chevy bell but also an adapter to mate it to the trans. Novak has it.
 

sdsupilot

CJ-8 Member
CJ-8.com Member
City
OKC
State
OK
#8
You can get an np241c from a 1990-91 suburban that is right hand output with a speed sensor in place of speedo cable. 1988-89 had a provision for speedo cable, but no speed sensor (I used pass through). Pass through speed sensor will allow you to use your factory speedo, and give the computer the speed data it needs.

That said, the t176 would likely be the most economical option. I love the my 700r4. Super smooth and easy for anyone to drive.

Do some research for front driveshaft clearance with the 700r4/4l60 with the 300. Without a lift it will be very very close to the pan.

Can’t really go wrong with either option.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#9
The iron duke 151 ci four cylinder used a standard chevy bell housing bolt pattern. If they installed a chevy I-6 engine, I bet they used that same bell housing.

If simplicity is the goal, the V-6 to iron duke bell housing to T-176 to D300 would be the easiest solution. Basically, just an engine swap, all else would remain the same with possibly a new flywheel.
 
City
Halifax
State
UK
#10
Thanks everyone but sorry guys i maybe should of explained i am in the UK where i cannot just go and get any car parts from a junkyard or parts store as most US cars are rare as rocking horse poop over here so i need to get Ir right first time or it starts getting very,very expensive to keep shipping things across!.

Bit of background history for you.
Scrambler originally came with the little 2.5 4 pot but someone installed a late 70s I6 4.1? engine in its place at some point.
It has 4.10 ratio axles which is good and also has a T176 that has the correct bell housing for a Chevy and that part i do know is right.
I thought the I6 flywheel would bolt up to the V6 but it has completely the wrong bolt pattern for the V6 crank and looks tiny compared to the flex plate..
If a Firebird flywheel definitely fits then i can get one ordered they are not too bad to ship over for what must weigh quite a lot.

Photo of the bellhousing
2.5 Bellhousing.jpg
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#12
Thanks everyone but sorry guys i maybe should of explained i am in the UK where i cannot just go and get any car parts from a junkyard or parts store as most US cars are rare as rocking horse poop over here so i need to get Ir right first time or it starts getting very,very expensive to keep shipping things across!.

Bit of background history for you.
Scrambler originally came with the little 2.5 4 pot but someone installed a late 70s I6 4.1? engine in its place at some point.
It has 4.10 ratio axles which is good and also has a T176 that has the correct bell housing for a Chevy and that part i do know is right.
I thought the I6 flywheel would bolt up to the V6 but it has completely the wrong bolt pattern for the V6 crank and looks tiny compared to the flex plate..
If a Firebird flywheel definitely fits then i can get one ordered they are not too bad to ship over for what must weigh quite a lot.

Photo of the bellhousing
View attachment 69718
Sure looks like an iron duke bell housing to me.

142467286_o.jpg

Jeep Forum discussion on the iron duke bell housing.

Now, how does the starter mount?
 
City
Halifax
State
UK
#13
I can see i need to do some more research to find a flywheel/clutch combination that works or just pay the chunk of money for the 4L60E box to D300 adaptor, but the starter mounts to the block with 2 long bolts from underneath that i can tell you.
 

Ron84cj

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
West Bend
State
WI
#14
Summit part # MU1675-1 I believe is correct. And use the firebird flywheel. I would call summit to verify this.
 
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