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I picked up a 28k 79 L82-4sp from the son of an old school drag racer who had passed.
Hopped in the car and drove it 200 miles home without a hitch.
as I started to take a close look at how the car is tuned I am curious if anyone is familiar with these types of modifications:
complete bypass of canister
breather placed on line to tank
T taken off PCV valve
vacuum from carb to canister to breather
carb to air plugged
pump removed
both manifold ports defeated
EGR removed
butterflies in snorkels removed along with associated vacuum lines
high performance distributor
cats removed
car really runs good however is running, in my opinion, very rich… trying to understand this “tune” before I start twisting mobs and pulling levers….
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
most of what you describe is for better flow, some of it maybe either issues he had bypassed or just thought it would give him more performance
complete bypass of canister...............canister may be plugged or just bad
breather placed on line to tank...........with the canister plugged there is no venting to the tank so this is the new vent
T taken off PCV valve........................he did away with the vacuum source to the emissions probably, get a get diagram
vacuum from carb to canister to breather... not needed with everything plugged or removed
carb to air plugged........................... with the doors removed its not necessary
pump removed................................. smog pump? just looking for more HP
both manifold ports defeated.............not familiar with what you are referring to..probably emissions I assume, he was looking for more power
EGR removed................................. .again hes looking for power
butterflies in snorkels removed along with associated vacuum lines...better flow for more power
high performance distributor..............more spark for better ignition, may have had the old dizzy go bad
cats removed................................. .better exhaust flow for more power.
THeres no telling which he thought was for power and which was bypassing an issue. I myself would get rid of the emissions controls just to have a cleaner looking and tidier engine compartment along with the performance benefits. It looks like its still all there just not doing its job. He may have been trying to hide that it was all bypassed for state inspections as well. As for running rich I have an AFR gauge installed so I can tune with it. Better than trying to read hot plugs and getting burned
I'm inclined to think he had a vacuum leak he couldn't find so he just bypassed everything, or he truly believed the old "emissions rob power" garbage. Most of the emissions components that were disconnected or bypassed, such as the EGR and EVAP, have zero effect at wide open throttle if the systems are working properly. As far as cats go, I don't know if your car is subject to emissions testing or not but, modern cats can flow more than even a well built engine could ever need.
How do you know it's a high performance distributor?
Did you check if it has stock advance springs or aftermarket?
Did you check initial timing?
Did you check if maximum mechanical advance occurs around 3k rpm and is 36 degrees?
Running rich, did you check spark plug color and heat range?
Check the timing. There are still vacuum hoses that can be removed, but the most important one appears intact: the vacuum advance. That should go to a manifold vacuum port on the distributor (please a few wide shots with the air cleaner removed, but it appears that it is connected to the correct port. Check with a finger or vacuum gauge, there should be vacuum signal at idle). The distributor vacuum advance has a hex by the nipple, indicating that it is adjustable, so be sure to see what effect the vacuum has on timing. For that, you'll need a Mity-Vac in addition to a timing light.
It's a bit unusual to find that the flappers have been removed from the dual snorkel intake, but the heat stove pipe is intact.
Yeah....kind of a major brainfart to open up the thermactor valves on the snorkles and leave the tubes so it can suck up all the good heated air........
Old school bracket drag modifications?
