backfiring, running rich
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
Depends on when it feels like it's getting too much fuel. If it's getting too much fuel as you're throttling it hard then smaller nozzle required. If too much fuel cruising and light throttle then jets. 80457's come with #64 jets. Which normally would be great for FE's. Did you buy this new?
Last edited by JEFFFAFA; Oct 14, 2013 at 10:51 AM. Reason: correction/addition
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
FE'S love fuel. 400's a different ball game. Especially since they are 2v's. This is the EXACT reason Ford dropped the 360/390 and replaced them with 351M/400. They knew they could never get them to pass emissions and get fuel economy outta 'em. Not trying to sound mean here at all. If I had a 400 mildly built with some real heads,mild cam,and some added compression ratio above the smogger pistons, I'd still only go about 63 jets. Note: factory fox chassis Mustang GT's came with #62 jets in their made for Motorcraft Holley 600's. 1979 through to the end of carbed 460's came with #61!!!!!!
Last edited by JEFFFAFA; Oct 14, 2013 at 07:18 PM. Reason: addition
Postmaster
Joined: Sep 2013
Posts: 2,595
Likes: 5
From: Pasadena, Ca
I thought #56 was stock for '79/400...i thought i read that here. I had 57 on it from PO and couldnt get it down to pass smog, and could smell gas a lot. I put in #54 to smog, and back up to #56.
Cant use headers in Ca😒
Cant use headers in Ca😒
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
Numbers on jets are not industry wide. They are only meant to compare to their own brand. A #63 Holley jet is not necessarilly the same inner dimension as a Motorcraft 2V #63 jet. Plus with headers most engines want fatter (I.E. richer) jets. Even Bikes.
Thread
Thread Starter
Forum
Replies
Last Post
rob-o
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
6
Jul 14, 2009 06:55 AM
notoriousLOG
1967 - 1972 F-100 & Larger F-Series Trucks
26
Jan 16, 2004 08:59 AM
