C1 '57 FI 9 Fin Valve Covers

[Michael W.]

The NCRS 56-57 JG indicates that at approx. VIN 2900, 1957 fuel injected optioned Corvettes converted from 9 fin to 7 fin valve covers. My '57 fuelie (VIN 3551) is relatively unmolested/unrestored and according to the second owner (he purchased the '57 in 1958 and sold it to me in 1993), this Corvette possessed 9 fin valve covers when he purchased it. The drivers side valve cover even has the cut out for the air meter.

I am curious as to how many other '57 fuelie owners (with original engines/valve covers) with VINs greater than 2900 also have the 9 fin valve covers. I have seen other examples of this--most recently in the April 2008 issue of VETTE magazine where an air box fuelie (VIN 4387) appeared to have 9 fin valve covers on the unrestored engine.

I understand that there was a transition period at the factory to convert from 9 fin to 7 fin--but how long did that take ? I am contemplating writing an article for Corvette Restorer regarding this subject. Feel free to correspond with me if your '57 fuelie > VIN 2900 has 9 fin valve covers.
Thanks!
Mike West

[Jack H.]

Re: C1 '57 FI 9 Fin Valve Covers

That's one of the hard call issues with a running change and the reason NCRS text typically applies a 'disclaimer' in descriptions (APPROXIMATELY VIN 2900). Generally, the factories did NOT round up and SCRAP on-hand parts built before a running change was made effective resulting in mixed-mode production until the last of the earlier parts were exhausted from the system.

I doubt you'll be able to pin a FIRM date on when the last car with 9-fin valve covers rolled off the assy line!

[Jack H.]

Re: C1 '57 FI 9 Fin Valve Covers

That's one of the hard call issues with a running change and the reason NCRS text typically applies a 'disclaimer' in descriptions (APPROXIMATELY VIN 2900). Generally, the factories did NOT round up and SCRAP on-hand parts built before a running change was made effective resulting in mixed-mode production until the last of the earlier parts were exhausted from the system.

I doubt you'll be able to pin a FIRM date on when the last car with 9-fin valve covers rolled off the assy line!

[Barry H.]

Re: C1 '57 FI 9 Fin Valve Covers

Mike, & Jack, My 51k mile orig 283 HP FI 57 s/n 3298 has 7 fins. I believe the fuel injected v/c switchover was done at Flint Eng Plant, in responce to clearance problems with v/c removal. Maybe because of demand, some of the last FI engines with 9 fins were sitting in stock bins at St Louis plant waiting for an order. (LIFO) After the switchover, I believe the later 245HP, & 270HP 2x4 engines at Flint were all built with the 9/fin v/c's to use up the old stock, so the transition would not be all at once. You will find 2x4 cars with much later s/nos with 9 fins. Could your FI be an 250HP eng?
Barry Holmes #940

[Barry H.]

Re: C1 '57 FI 9 Fin Valve Covers

Mike, & Jack, My 51k mile orig 283 HP FI 57 s/n 3298 has 7 fins. I believe the fuel injected v/c switchover was done at Flint Eng Plant, in responce to clearance problems with v/c removal. Maybe because of demand, some of the last FI engines with 9 fins were sitting in stock bins at St Louis plant waiting for an order. (LIFO) After the switchover, I believe the later 245HP, & 270HP 2x4 engines at Flint were all built with the 9/fin v/c's to use up the old stock, so the transition would not be all at once. You will find 2x4 cars with much later s/nos with 9 fins. Could your FI be an 250HP eng?
Barry Holmes #940

[Mike M.]

Re: C1 '57 FI 9 Fin Valve Covers

57 vin 1093, a 250 hp powerglide, has 9 fin vc. 57 vin 4450, a 283 hp, has the 7 fin vc.i have seen barry holmes 57 fi and believe its valve covers to be the originals to the car. mike

[Mike M.]

Re: C1 '57 FI 9 Fin Valve Covers

57 vin 1093, a 250 hp powerglide, has 9 fin vc. 57 vin 4450, a 283 hp, has the 7 fin vc.i have seen barry holmes 57 fi and believe its valve covers to be the originals to the car. mike

[John D.]

Re: C1 '57 FI 9 Fin Valve Covers

Barry, Nice to see you posting for a change. Over the years these 9 fin versus 7 fin have always been a topic of discussion. I have had the pleasure of seeing various 9 fin covers that were in fact installed on later cars that our guide line calls for. That 9 fin cover is a high quality cover isn't it. I mean that casting is very heavy compared to the typical 7 fin and up cover. Might even be a different alloy as the aluminum has a different texture and look to it when refinished.
I like the last line in your post. In our Pittsburgh Chapter there are more 57 Corvette owners than in most of the NCRS chapters of its size. A lot of the guys are old like you (and me) and claim that the 9 fin valve covers did in fact exist in much late 2X4 cars. I remember Larry Fellers and others discussing this. You were there. John D.

[John D.]

Re: C1 '57 FI 9 Fin Valve Covers

Barry, Nice to see you posting for a change. Over the years these 9 fin versus 7 fin have always been a topic of discussion. I have had the pleasure of seeing various 9 fin covers that were in fact installed on later cars that our guide line calls for. That 9 fin cover is a high quality cover isn't it. I mean that casting is very heavy compared to the typical 7 fin and up cover. Might even be a different alloy as the aluminum has a different texture and look to it when refinished.
I like the last line in your post. In our Pittsburgh Chapter there are more 57 Corvette owners than in most of the NCRS chapters of its size. A lot of the guys are old like you (and me) and claim that the 9 fin valve covers did in fact exist in much late 2X4 cars. I remember Larry Fellers and others discussing this. You were there. John D.

[Ed H.]

Re: C1 '57 FI 9 Fin Valve Covers

Barry,
My original 270hp 57 came with 9 fin v/c, VIN # 3745

[Randy G.]

Re: C1 '57 FI 9 Fin Valve Covers

My VIN 3367 FI 283 HP has 9 fin with cut out.