Sc engine questions

[sylvester]

I have a question. does anyone knows how to tell a 79 engine from a 80s engine without opening up the engine. I'm confused what engine it is because it has no engine numbers. car is 79 sc. here's the strange part that's confusing me. The distributor has two vacuum lines. that look like 80. but the heads looks to have the holes for the pump. of 79. please help I'm very confused thank you.

[gazzerr]

Post a pic and the guys will chime in.

[sylvester]

ok... I will upload some pictures tomorrow

[boyt911sc]

Sylvester,

If I would attempt to identify your engine by visual inspection from the outside, I would check the following:

a). Look at the engine number/engine type
b). RoW/Euro or USA/CAN, etc.
c). Intake runners (2R or 4R).
d). ‘79 SC’s do not use OXS, ‘80 SC US/CAN does.
e). Ignition distributor number of vacuum line/s.
f). Presence of temp. switch 15°C @ chain cover (4-5-6).
g). Presence of FV. ‘79 never had one.
h). Airbox.
i). Brake vacuum from air box.
j). Fuel return line.
k). Aluminum vac. tubes to AAR and DV.
l). WUR
m). FD
n). Decel valve
Etc.

These are some of the distinct differences between a ‘79 and ‘80 US models on top of my head and probably I missed a lot more. Keep us posted.

Tony

[sylvester]

Thanks Tony I will report back with that information soon as possible sir thank you.

[boyt911sc]

Sylvester,

Look at the alternator fan housing part number.

930.106.101.0R (226 mm ID) for ‘78~’79.
930.106.102.0R (245 mm ID) for ‘80~’83.

Post pictures so others could see what you have.

Tony

[sylvester]

Engine update.... with a very weird outcome. man my car is a 79 but has all the 80s engine features. has 2 vacuum lines on distributor, dme cpu under pass seat, has frequency valve, bosh fd #0438100077, that almost seal the deal for me. kinda make me belive that this is a 80s engine. also looks like it has 80s runners and 4 79 runners. so i think the guy that had my car before me was was looking for low end power. what do you guys think. i can send pictures tell me which ones to send my mystery is almost solve thanks for the help guys.

[boyt911sc]

Originally Posted by sylvester

Engine update.... with a very weird outcome. man my car is a 79 but has all the 80s engine features. has 2 vacuum lines on distributor, dme cpu under pass seat, has frequency valve, bosh fd #0438100077, that almost seal the deal for me. kinda make me belive that this is a 80s engine. also looks like it has 80s runners and 4 79 runners. so i think the guy that had my car before me was was looking for low end power. what do you guys think. i can send pictures tell me which ones to send my mystery is almost solve thanks for the help guys.

Sylvester,

Maybe you have a ‘79 chassis with an ‘80 SC engine. PM me the vin # and related information. Thanks.

Tony

[sylvester]

That's okay I realize someone change the engine. but I really wanted a 79 engine but that's okay. the end no reply needed thank you.

[kent olsen]

I rebuilt an 80 engine for my 72. Yes they have smaller valves which don't help top end horsepower but then top end horsepower is only there at top end. It's torque that pulls the car.

I also added a custom cam that dropped the peak torque even lower. Mines a street/track car. Now when you come out of a turn the torque sling shots you as soon as you hit the gas and you don't have to wait for the rpm's to build.

[sylvester]

Hey Kent I don't know that much about intake runners. but the guy that had my 79 before me. rebuilt my 80s engine. I don't know what type of cam he put. but he also did a cat delete. and somehow he put 3 80s intake runners. and 3 79 runners. and it feel like I'm riding a sport bike. Throttle response is super quick.

[kent olsen]

Throttle response, right, that's what you need.

My 65 corvette big block has 430 ft/lbs of torque at 2000rpm, thats throttle response!!

[Bob Kontak]

Originally Posted by kent olsen

My 65 corvette big block has 430 ft/lbs of torque at 2000rpm, thats throttle response!!

Those had one barrel Rochesters, right?

[john walker's workshop]

79 and 80 air boxes have different size outlets for the respective years, so mixing intake runners wouldn't work.

[sylvester]

Yes you're right. but some kinda way there on there. Unless they put the wrong stamp on the runners. because 3 of them says 79 the others says 80. like i stated in my earlier post. i dont know that much about runners.
school me if I'm missing something. thank you for the reply.

[sylvester]

it has 2R stamp and 4R stamp.

[boyt911sc]

Originally Posted by sylvester

it has 2R stamp and 4R stamp.

Intake runners -2R are 34 mm ID used in ‘76~’77 and ‘80~’83 SC (US spec.) while intake runners -4R are 38 mm ID used in ‘78~’79 SC (US spec.) and ‘78~’83 SC ROW.

Previous owner was probably not aware about the difference between these intake runners. But the individual who installed them should have found the difference during installation unless intentionally done. The rubber boots are different and so with the airbox. No way someone would use them for his own engine unless wanting to deceive the prospective owner.

Tony