Topic: Big Block to 502 Swap
in Forum: C3 Engines
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Former Member
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Castle Rock, CO - USA
Joined: 4/21/2002
Posts: 179
Vette(s): 1973 T-Top
1993 Coupe
Hello Randy,
The swap should be fairly straight forward.
You will need an in-line fuel pump as there is not a place to put the mechanical pump.
You will need to replace the water pump with a "short" water pump.(If the engine you buy has a pump already on it.) There may be some minor clearance problems with the timing cover bolt heads. Alittle grinding should help.
Have the radiator rodded out or replaced with a new one. I don't believe that you need to go to any great lengths to keep the engine cool if the cooling system is in good shape.
The accessories and pulleys should bolt exactly in place.
As far as the hood clearance, it depends on your year. 68-72 should not have any problems. Their hoods are high enough to clear most intakes. The Edelbrock Performer is about the right height but whatever you choose make sure to compare it to the original for height. It shouldn't be any more than 1/4" taller. 73-74 BB intakes are actually very short. You can use the original intake on the 502 I think, but HP will suffer since the intake runners actually run uphill to the intake ports.
Good luck!
Alex
|UPDATED|4/29/2004 6:46:54 AM (AZT)|/UPDATED|
The swap should be fairly straight forward.
You will need an in-line fuel pump as there is not a place to put the mechanical pump.
You will need to replace the water pump with a "short" water pump.(If the engine you buy has a pump already on it.) There may be some minor clearance problems with the timing cover bolt heads. Alittle grinding should help.
Have the radiator rodded out or replaced with a new one. I don't believe that you need to go to any great lengths to keep the engine cool if the cooling system is in good shape.
The accessories and pulleys should bolt exactly in place.
As far as the hood clearance, it depends on your year. 68-72 should not have any problems. Their hoods are high enough to clear most intakes. The Edelbrock Performer is about the right height but whatever you choose make sure to compare it to the original for height. It shouldn't be any more than 1/4" taller. 73-74 BB intakes are actually very short. You can use the original intake on the 502 I think, but HP will suffer since the intake runners actually run uphill to the intake ports.
Good luck!
Alex
|UPDATED|4/29/2004 6:46:54 AM (AZT)|/UPDATED|

Clifton, NJ - USA
Joined: 10/3/2003
Posts: 129
Vette(s): 1972 Coupe
Ontario Orange
Black leather interior
LS-5; Turbo 400
Randy;
Check with the manifold mfgrs, Edlebrock says none of their dual plane manifolds will fit under the stock BB hood, the only manifold they have that will is thier Torkerr II. I'm looking at putting Edelbrocks' EFI system on my 72 BB, and figure I would need to go to a L-88 hood for clearance.
NJ BB Ken
Check with the manifold mfgrs, Edlebrock says none of their dual plane manifolds will fit under the stock BB hood, the only manifold they have that will is thier Torkerr II. I'm looking at putting Edelbrocks' EFI system on my 72 BB, and figure I would need to go to a L-88 hood for clearance.
NJ BB Ken

1972 T Top 454; "Boomer" Latest "upgrades": 1 1/8" front Stabilizer bar. Rebuilt SS calipers with O-ring pistons. Under car Chambered exhaust. Fiberglass rear spring (360lbs/in). Bilstein Rear Shocks. 3/4" Rear Stabilizer Bar. Tow hitch. Performer manifold with 600 cfm Holley. Comp Cam 262 .499 lift. L-88 Hood in process

Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
if you do get the l-88 hood...
the edelbrock air-gap fits nicely with a demon sitting on it.
the edelbrock air-gap fits nicely with a demon sitting on it.
Former Member
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Castle Rock, CO - USA
Joined: 4/21/2002
Posts: 179
Vette(s): 1973 T-Top
1993 Coupe
Hello,
The short water pump is used to get the needed clearance from fan to radiator. The BB you have currently has the short pump.
The BB intakes for the 69 were not very high, but they had adaquate performance. I am assuming you have the 390hp engine. You may be able to clean up the ports and still be near the 500hp mark. Also the 68-69 Tripower will fit under the hood. You will need to match up the type port (oval or square) to the heads on the 502. I think they are oval on the 502. So the 390hp and 400hp (tripower) will be a direct fit. The 435hp tripower is a square port and should not go on the oval port head.
Alex
The short water pump is used to get the needed clearance from fan to radiator. The BB you have currently has the short pump.
The BB intakes for the 69 were not very high, but they had adaquate performance. I am assuming you have the 390hp engine. You may be able to clean up the ports and still be near the 500hp mark. Also the 68-69 Tripower will fit under the hood. You will need to match up the type port (oval or square) to the heads on the 502. I think they are oval on the 502. So the 390hp and 400hp (tripower) will be a direct fit. The 435hp tripower is a square port and should not go on the oval port head.
Alex
in Forum: C3 Engines
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