390 Differences
Postmaster
Joined: Mar 2011
Posts: 2,698
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From: Taxachusetts
Off the top of me head:
Truck FE engines from the factory had a lower compression ratio (8.5:1 ?) than cars (~9.5:1?), but more torque and less overall HP.
Less gross valve lift than cars......not sure of the main webbing being any different...as in the Modified truck vs car engines.
The search function is your friend.....
Truck FE engines from the factory had a lower compression ratio (8.5:1 ?) than cars (~9.5:1?), but more torque and less overall HP.
Less gross valve lift than cars......not sure of the main webbing being any different...as in the Modified truck vs car engines.
The search function is your friend.....
Cargo Master
Joined: Dec 2015
Posts: 2,549
Likes: 331
From: Harned, Ky
Pickup truck and car 390's are basically the same, they could have different compression ratio's, cams, timing chain sets, ect which also varies between year models. 391 HD truck engines are a different animal, block has a larger hole for the governored dist shaft and larger oil pump drive, heads, intake, crank, timing set, front timing cover, water pump are all different.
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Joined: Apr 2004
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Car 390 for '68 would be 9.5 CR for the 2bbl with a dished piston. 10.5 for the 4bbl with a flat top piston. Compression height for both was approx. 1.77". Pistons were .010-.030 below deck. Cams were probably different. Heads may have had slightly smaller combustion chambers.
Truck 390 had compression in the 8s, maybe 8.2. The piston used in these motors is the same spec as the Mercury 410 piston. The compression height is appox 1.66". Thus the piston is down the hole .100+. Heads with casting code of D2TE would have had hardened valve seats.
How does it run? Any valve train noises?
Truck 390 had compression in the 8s, maybe 8.2. The piston used in these motors is the same spec as the Mercury 410 piston. The compression height is appox 1.66". Thus the piston is down the hole .100+. Heads with casting code of D2TE would have had hardened valve seats.
How does it run? Any valve train noises?
Mountain Pass
Joined: Nov 2004
Posts: 140
Likes: 2
From: Monroe, WA
Ford published 390 engine specs 1968 full size vs 1972 truck
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
If you're basing this assumption on the casting numbers on the block, then you're mistaken about it. Pickups and cars got the same block, crank, rods, intake and heads. C8 block would have been used for several years until the next block revision. The only different parts would have been the pistons, camshaft, carb and distributor. Plus the exhaust manifolds. FE's probably had more parts combinations than any other engine line. And you'll never know what's inside one till you take it apart. Are you sure that you have a 390 and not a 360 ? (or something else)
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Mountain Pass
Joined: May 2004
Posts: 100
Likes: 0
From: Alberta
If you're basing this assumption on the casting numbers on the block, then you're mistaken about it. Pickups and cars got the same block, crank, rods, intake and heads. C8 block would have been used for several years until the next block revision. The only different parts would have been the pistons, camshaft, carb and distributor. Plus the exhaust manifolds. FE's probably had more parts combinations than any other engine line. And you'll never know what's inside one till you take it apart. Are you sure that you have a 390 and not a 360 ? (or something else)
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Mountain Pass
Joined: May 2004
Posts: 100
Likes: 0
From: Alberta
Car 390 for '68 would be 9.5 CR for the 2bbl with a dished piston. 10.5 for the 4bbl with a flat top piston. Compression height for both was approx. 1.77". Pistons were .010-.030 below deck. Cams were probably different. Heads may have had slightly smaller combustion chambers.
Truck 390 had compression in the 8s, maybe 8.2. The piston used in these motors is the same spec as the Mercury 410 piston. The compression height is appox 1.66". Thus the piston is down the hole .100+. Heads with casting code of D2TE would have had hardened valve seats.
How does it run? Any valve train noises?
Truck 390 had compression in the 8s, maybe 8.2. The piston used in these motors is the same spec as the Mercury 410 piston. The compression height is appox 1.66". Thus the piston is down the hole .100+. Heads with casting code of D2TE would have had hardened valve seats.
How does it run? Any valve train noises?
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Hotshot
Joined: May 2003
Posts: 11,141
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From: south louisiana
Car 390 for '68 would be 9.5 CR for the 2bbl with a dished piston. 10.5 for the 4bbl with a flat top piston. Compression height for both was approx. 1.77". Pistons were .010-.030 below deck. Cams were probably different. Heads may have had slightly smaller combustion chamber
Hotshot
Joined: May 2003
Posts: 11,141
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From: south louisiana
At this point in time, the only sure way to know is to take it apart. Could be any combination of parts there. Heads are easy to Id, the casting numbers are between the two middle spark plugs. You can Id the piston type with a bore scope thru the spark plug holes. The stroke is a little harder but can be measured pretty close by sticking a rod in the spark plug holes and rotating the crank and doing the math to figure the stroke.
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