360 to 390 question
Thread Starter
|
New User
Joined: May 2014
Posts: 14
Likes: 0
360 to 390 question
Hey guys, first post with a little question. I just bought a 1971 ford f100 and looking at things to do. it came with a 360 2 bbl, and i rigged up a temporary tank and she kicked right over, runs like a top, no knocking, smoking, nothing. Reads 60,xxx miles (probably rolled once) and ive looked at some hop ups. It has some oil leaks so i was going to throw in a full gasket kit and that gives me a chance to inspect in guts for anything wrong. Id like to throw a mild cam, 4bbl on it too. Looking at the 360 to 390 conversions i looked at the local junkyard and found a 390 from a '69 galixie 500. no intake so some of the pinions might be junked. Can i just swap con rods and crank up to my pistons? Is this suggested or to much work; not to take apart my good running block? Any kind of input is appreciated!
Super Moderator
Joined: Apr 2004
Posts: 34,524
Likes: 2,829
Welcome to FTE.
The 360 uses a 390 car spec piston from the '66 on 390. It seems like Ford used both the "Regular Fuel" 2bbl motor piston and the "Premium Fuel" 4bbl motor piston. The 2bbl was 9.5 compression, and the piston had a slight dish and 4 valve reliefs. The 4bbl was 10.5 compression, with a flat top piston and again 4 valve reliefs.
That '69 motor was probably a 4bbl--why else would an 80+ pound manifold be missing?
Anyway, since your 360 already has 390 pistons in it, the crank and rod swap will work. Probably better with the dished pistons as 10+ compression is going to require more expensive gas.
Beware any ridge in your cylinders as your pistons are going go right over it, so you may want to clean that up with a hone.
Your 360 suffers the low compression due to those pistons sitting down the hole on top of that shorter stroke. However, several folks here report more than satisfactory results with headers and a small 4bbl on an otherwise stock 360, despite the low compression.
Read on in this forum. I would venture to say you will find about 2 "360 to 390" or similar build threads per month for the last 10 years here....
The 360 uses a 390 car spec piston from the '66 on 390. It seems like Ford used both the "Regular Fuel" 2bbl motor piston and the "Premium Fuel" 4bbl motor piston. The 2bbl was 9.5 compression, and the piston had a slight dish and 4 valve reliefs. The 4bbl was 10.5 compression, with a flat top piston and again 4 valve reliefs.
That '69 motor was probably a 4bbl--why else would an 80+ pound manifold be missing?
Anyway, since your 360 already has 390 pistons in it, the crank and rod swap will work. Probably better with the dished pistons as 10+ compression is going to require more expensive gas.
Beware any ridge in your cylinders as your pistons are going go right over it, so you may want to clean that up with a hone.
Your 360 suffers the low compression due to those pistons sitting down the hole on top of that shorter stroke. However, several folks here report more than satisfactory results with headers and a small 4bbl on an otherwise stock 360, despite the low compression.
Read on in this forum. I would venture to say you will find about 2 "360 to 390" or similar build threads per month for the last 10 years here....
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
redlinemotorsportts Welcome to 
and the FE forum 
Since the 360 and 390 are the same bore, grab the crank and rods only from the car engine, and do a complete rebuild. You will need a new piston set for the .20 or .30 bore that likely will occur.
John
and the FE forum Since the 360 and 390 are the same bore, grab the crank and rods only from the car engine, and do a complete rebuild. You will need a new piston set for the .20 or .30 bore that likely will occur.
John
Elder User
Joined: Nov 2009
Posts: 891
Likes: 0
From: Mayfield, KY
First make sure what you will need. Then price it accordingly. I have found I could save $ buying my parts on eBay. You just have to know what parts you are looking for as most sellers cant list every application.
Thread
Thread Starter
Forum
Replies
Last Post
Martin Torres
1957 - 1960 F100 & Larger F-Series Trucks
9
Sep 4, 2016 01:13 PM
ygoldsberry
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
14
Mar 5, 2012 05:43 PM
mikeo0o0o0
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
3
Aug 17, 2011 06:14 PM
SuperFord
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
5
Sep 17, 2004 10:17 AM
Jsbiohazard
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
6
Mar 13, 2003 06:23 AM
