Modifing 460 FI cam timing
Thread Starter
|
Senior User
Joined: Nov 2010
Posts: 173
Likes: 0
Modifing 460 FI cam timing
A guy I know replaced the cam chain and gears on his 93 FI 460 with a 1970 429 cam gear kit.
This was just a simple can chain and gear swap and NOTHING else!
It is well known that one of the ways of meeting smog on the more modern? engines was to retard the cam a few degrees as compared to the previous engines BUT this is the first real evidence that I have seen on the 87 and up FI 460 engines as to possibe improvement in performance, operbility and economy.
1. He says the engine starts and runs better than on the RC set
2. He says the engine accelerates faster
3. He says the engine gets at least 1 MPG better than before the swap.
4. He says the engine has enough extra power that it now will stay in OD where before it would downshift back to 3 rd
5. He says after a trip from Florida to North Carolina pulling a heavy trailer loaded to 6000 on the return trip he has seen no down side to the simple upgrade.
Some issues I have:
His old cam set was worn and chain streached so his initial setup was not in good shape.
Perceived improvements have a mental component; IE If I install something it had to be an improvement.
BUT 1 mpg improvement is certainly measurable but could be partly due to the chain being worn out before!
_____ I have a freshly overhauled 460 FI in our work truck with a new stock cam and kit so I would like a general online discussion prior to tearing back into it and swapping out the kit.
The one thing absolutely established is the the eariler cam kit works in the FI engine with no negative effects observed.
Has anyone else seen any measurable improvement on the FI engine by simply going to the straight up cam from an earlier engine configuration???
This was just a simple can chain and gear swap and NOTHING else!
It is well known that one of the ways of meeting smog on the more modern? engines was to retard the cam a few degrees as compared to the previous engines BUT this is the first real evidence that I have seen on the 87 and up FI 460 engines as to possibe improvement in performance, operbility and economy.
1. He says the engine starts and runs better than on the RC set
2. He says the engine accelerates faster
3. He says the engine gets at least 1 MPG better than before the swap.
4. He says the engine has enough extra power that it now will stay in OD where before it would downshift back to 3 rd
5. He says after a trip from Florida to North Carolina pulling a heavy trailer loaded to 6000 on the return trip he has seen no down side to the simple upgrade.
Some issues I have:
His old cam set was worn and chain streached so his initial setup was not in good shape.
Perceived improvements have a mental component; IE If I install something it had to be an improvement.
BUT 1 mpg improvement is certainly measurable but could be partly due to the chain being worn out before!
_____ I have a freshly overhauled 460 FI in our work truck with a new stock cam and kit so I would like a general online discussion prior to tearing back into it and swapping out the kit.
The one thing absolutely established is the the eariler cam kit works in the FI engine with no negative effects observed.
Has anyone else seen any measurable improvement on the FI engine by simply going to the straight up cam from an earlier engine configuration???
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 39
From: EXTREME southwest CT
FI 460 engines were not retarded.
They have a "straight up" single roller chain and gear set from the factory.
The only thing he did by using a pre '70 chain in his truck is to assure the Hyvo/Morse style chain will wear out in 50K or less and need replacing.
It was only the 71-'87 carbureted 'emissions' engines that were 4* retarded.
They have a "straight up" single roller chain and gear set from the factory.
The only thing he did by using a pre '70 chain in his truck is to assure the Hyvo/Morse style chain will wear out in 50K or less and need replacing.
It was only the 71-'87 carbureted 'emissions' engines that were 4* retarded.
Thread
Thread Starter
Forum
Replies
Last Post
loveless41908
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
5
Jan 23, 2017 08:03 AM
Shark Racer
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
7
Jul 28, 2010 09:50 PM
IBeam
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
5
Mar 10, 2006 06:23 PM
scottie2hottie
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
7
Sep 30, 2004 08:53 PM
Thudpucker
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
4
Aug 27, 2001 09:32 PM
