[1980 Avanti II - Engine Displacement]

1980 Avanti's came with 350ci engines; you may be thinking of 1970... I can't recall specifically, but some Avanti's had 400ci engines in the very early 70's. GM made 400ci engines from about 1970 to as late as 1980. One way to tell a 400ci block is that nearly all of them have casting provisions for 3 freeze plugs on each side rather than the 2 that are normal on smaller displacement engines, although only 2 freeze plugs were machined on some of the 400ci blocks (but, see below).

Every Chevy small block has a 6 or 7-digit casting number on top of the engine's bellhousing "collar" on the driver side; the stamped numbers on a small pad extending out in front of the passenger side head indicates the vehicle VIN (for Chevy-produced vehicles, not Avanti's) along with codes for place and date of manufacture, horsepower, and transmission type. The 3951509 block casting had only the standard 2 freeze plug provisions, and that 400ci engine was last produced in 1980.

It's always possible, of course, that the engine currently in the car is not original to the car, in which case the casting and stamped numbers might help identify it.

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[1980 Avanti II - Engine Displacement]

1980 Avanti's came with 350ci engines; you may be thinking of 1970... I can't recall specifically, but some Avanti's had 400ci engines in the very early 70's. GM made 400ci engines from about 1970 to as late as 1980. One way to tell a 400ci block is that nearly all of them have casting provisions for 3 freeze plugs on each side rather than the 2 that are normal on smaller displacement engines, although only 2 freeze plugs were machined on some of the 400ci blocks (but, see below).

Every Chevy small block has a 6 or 7-digit casting number on top of the engine's bellhousing "collar" on the driver side; the stamped numbers on a small pad extending out in front of the passenger side head indicates the vehicle VIN (for Chevy-produced vehicles, not Avanti's) along with codes for place and date of manufacture, horsepower, and transmission type. The 3951509 block casting had only the standard 2 freeze plug provisions, and that 400ci engine was last produced in 1980.

It's always possible, of course, that the engine currently in the car is not original to the car, in which case the casting and stamped numbers might help identify it.

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[1980 Avanti II - Engine Displacement]

I am looking at an ad for a 1980 Avanti II, the ad listes the engine as a 350. I thought that the 1980 use the 400 small block. I haven't yet seen the car but I suspect that the seller simply doesn't know the correct engine size. I don't know the Chevy engines that well. How would I tell if the engine is a 350 or a 400?

[Mid 70 Front Bumpers (cow catchers)]

Both.  The main assembly unbolts from circular frame mounted extensions which in my case I cut off with a sawzall and a 5 pack of metal cutting blades.  Some people just do the unbolting part and use the frame mounts for mounting fog lights.

Paul

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Thanks,

In my opinion, the car looks a lot better with them off.

Sam,

[Mid 70 Front Bumpers (cow catchers)]

Both.  The main assembly unbolts from circular frame mounted extensions which in my case I cut off with a sawzall and a 5 pack of metal cutting blades.  Some people just do the unbolting part and use the frame mounts for mounting fog lights.

Paul

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[Mid 70 Front Bumpers (cow catchers)]

I have been looking to buy an Avanti. I see that many of the early to mid 70's have a 5mph supplemental bumper installed as original equipment. I see that in a lot of cases this device has been removed. Is the removal of this supplemental bumper system difficult or is it simply a bolt on device.

Thanks for your reply.