Dusty
Friend stumbled onto a 69 amc 390 may reach out and pick it up for transplanting into a cherokee or a cj my questions are
1. it has no brackets so can the later 70+ v-8 brackets work? if i recal the pre 70 motors are shorter deck.
2. it has the square port heads, i would like to upgrade to dog leg heads so can the block be drilled out and retapped to 1/2" head bolts.
3. will a later timing cover (new timing cover) and complete felpro 1970+ gasket set work on on it?
4. Are the motor mounts the same?
5. Was there something goofey about the bell pattern that im forgetting
the timing cover is cracked and one head was damaged when it sucked a vavle. block crank and rods are fine.
111!!! would much rather find a 1970 390 but good luck. doing a 390 would just be fun but may be too much work for too little differenc between it and the 401.
MC now i remember what i was supposed to ask you today when i called. all of the above i could have just posted it but ive been a once a week net junkie lately
Dusty
tufcj
1966-1969 are GEN2 engines, 1970 up are GEN3. The deck height is shorter, as is the stroke. When they made the blocks taller in 1970, they lengthened the stroke too, the 390 became a 401 (the bores are the same). The 390 crank has a smaller diameter flat flange on the back, so you need the correct flywheel or flexplate for the crank. The pilot hole in the back is too small for automatics (TH400 or any TF). It can be machined, but the crank would need to be pulled. Later dog leg heads can be swapped on using step dowels (available) and the 7/16" bolts. No need to drill the block for 1/2 inch bolts. Unless you use 1970 heads, your compression will drop some (1/2 to 1 point, depending on what you read). Early motors (thru 71?) had a shorter water pump and pulleys, along with a 3 bolt lower pulley. Later models had taller, 4 bolt lower pulleys. All the accessory brackets and motor mounts bolt up the same, and the water pumps will swap, as will timing covers. Bellhousing bolt patterns are the same. It's just a matter of finding the right mix of parts.
I've got 70 heads on my 69 390 block, using 7/16 bolts and step dowels. I think Fel-Pro only lists 2 gasket kits, one for the 290/304, and another for the 343/360/390/401.
Bob
tufcj
Dusty
Thanks bob,
howd that R4B work for you? iirc you bought from me.
i told him about the inability to bolt it right up without maching the crank for a T400. so instead he'll stay with the first plan of putting it in his cj5, going to be married to a t-18. taking out a dead 401 he is looking at the 390 as a fun spinner motor for his jeep 512/525 lift 226/230 dur@50 112* lobe seperation cam (this was a good cam in a 401 powered jeep, a hair on the large side but nothing that the 401 didnt swallow and idle over rocks with still), or at least that is one option the othr cam is a 512/512 224/224 108+4 lobe seperation with (i have no idea what that meant but thats what the card said. LOL). spare cams we have lying around. he wants to shoot for fairly high compression 10.25-11.5:1 have both a set of 51 cc heads and 58 cc heads so he knows he can steal either of those from me. can a 401harmonic balancer be balanced and fitted onto a 390 to gain the four bolt holes or didnt some 360s or 304s come with 3 holes?
is the 69 390 like the 401 in that main bolts can be replaced with ARP - 351 Cleavland 2 bolt main studs also are rod bolts the same between 69 and the later 401s. how about pushrod length cant get away with the old .010 longer chevy pushrods i assume when running roller rockers so what did you end up with there?
are you running pump gas still in yours, what compression ratio did you end up with. Thats good news that the later brackets will work. where did you get your pistons? ebay has 390 flywheels so i think he can get one reasonable otherwise i imagine that bulltear has a line one them. What are your thoughts of the 390 being used in place of his 401 for his jeep. i think its a cool idea a a little less stroke???? to play with.
im open to your thoughts even if you saay hes nuts stay with the 401 cause we are still beer-bating this one as he has two- three months to get her together and get er back on the trail
thanks
dusty
tufcj
During the course of the winter, I moved from Denver to the Chicago area. Job transfer, not really by choice. The company I work for shut down about 90% of it's operation in Denver, and I'm only about 2 1/2 years short of a full retirement. So the choices were to go to Chicago or New Jersey for a couple of years until I can retire.
My CJ has been in storage at my mom's house about 35 miles SW of Chicago since November. I did start it last weekend and let it run about 1/2 hour.
My friends took me on a final Colorado trip in October, before I left. Went on a little used trail called Winding Stairs. I ripped an upper shock mount off the frame and lost a shift rail cap, the t-case pumped all the lube out and hurt the bearings. One of my buddies laid his Toyota over.
I've finally got my garage (4 car :!: ) set up and wired for 220, so my compressor and welder are back online. I plan on getting the Jeep back home in a couple of weeks. Then it gets some long overdue TLC, including the R4B. I just brought that and some other engine parts home from mom's last weekend.
Bob
tufcj
