Whats up guys? So I've done a lot to my 78 but I'm to a point where I feel like I'm pretty tapped out in regards to performance upgrades on this C3 without dumping thousands of $$$ into her...not that I havent done that already. She's already quick, but I guess I'm looking for any potential cheap or affordable upgrades/tricks to get a few more horses out? I'll list what all has been done and let you guys decide for now if there's anything left besides tearing the motor down(which is out of the question by the way).
-Original Heads w/ bored out intake and exhaust valve's with SS swirl polished valves
-Crane Cams 270/470 lift cam
-Edelbrock Polished Performer Intake
-Underdrive Pulleys
-Dynomax Full Length Headers
-3.70 Rear End
-Shift Kit
-AC Rapid Fire Plugs
-Accel 8.8 Racing Wires
-MSD Ignition & Distrib.
-High Flow Water Pump
-Be Cool Stage 4 SS Radiator
-Electric Fans
-K&N Air Filter
-K&N Oil Filter running Royal Purple 10w-30
-Removal of all Smog/EPA equipment(pumps,hoses,cat)

So, I'm not looking to tear the motor down to the point of replacing pistons or going radical with a supercharger, etc. I guess I just cant seem to come up with anything else featuring "bolt on" performace or cheaper upgrades as in replacing the rear end(as I recently did) from the factory 3.08 to a 3.70. In case your thinking stall convertor, not really wanting to do that b/c I wanna be able to drive the car for a while if I want to without burning up the tranny after a period of time. Again, not sure if theres anything left to do or any tech tricks someone might have to crank out a few more horses or any ideas on cheaper upgrades? Thanks...

 

turbo,supercharge,or nos. 100 hp right off the bat.I run boost and nos.
All bolt up kits

 

Yea, but not wanting to go NOS or anything "unnatural"...too many horror stories of blowing things up with spray. Plus I like all-natural!

 

A hundred shot is pretty safe

 

Good luck, your pretty much maxed out.

 

all throttle ,no bottle

 

fabricate something so the motor always breathes amient temp air and not hot-n-nasty under-hood air.

also, start finding places to shed pounds.

 

You haven't mentioned what carb you have.

 

A higher stall convertor ..2400 for example would make a huge difference especially with that new set of 3.70 gears..it would get you into your power range instantly,and with a tranny cooler the life of your tranny would never be an issue..Alot of people run much higher stalls on the streets and have no issues or concerns.For other parts and pieces you could bolt on /add ..roller rockers,electric fuel pump,H or X pipe to your exhaust,what carb are you running?

 

Honestly, carb won't make much of a difference at this point. The Q-Jet is still a 750 cfm mechanical secondary carb that will work well if tuned properly.

My $0.02, new heads are the answer. The '77 heads are a turd and you can only polish a turd so match. Just ading larger valves will not help that much.

A set of decent aluminum heads will flow much better and you can pick up 30-50 hp with just that swap. The best would probably be the AFR 180's but they are not the cheapest.

 

Well I am running the factory Rochestor Quad and its set up to a tee! Thought about a Demon, but dont wanna alter the carb thats on there as the set up I have runs great in that retrospect. The ambient air idea is a good start, not sure how to create something like that. With the way the hood opens on the c3 and crammed tight headlight area, itd be hard to make a cold air intake type device. I do have the hood with the holes on the side of my hood so it can breathe a little better. I guess I could always cut holes in the hood but obviously dont wanna go through all that...lol.

 

In regards to exhaust...lol, I'm running open headers right now...haha. No worries in regards for x-pipes/h-pipes/etc. As for an electric fuel pump, I'm not having any issues with not getting enough gas...I have a sufficient amount of gas...not having trouble in that area in regards to it not supplying enough. Not sure adding an electric fuel pump would help any in the way of HP. What do you think? I had comp cams 1.6 roller rockers but when I had my heads done, I talked with a guy who actually specialized in corvette head rebuilds and his advice was to trash the roller rockers and go back to the factory rockers...he said he's seen time and time again where when the heads are set up right, the rockers actually make no difference and actually advised he's seen more gain from the factory rockers than aftermarket. Any ideas anyone on iridium plugs? I mean I know were to a point of small gains now, but hey, what have I got to lose if its something that simple?

 

Hey SteveG75, I checked out the AFR 180's...Might be wrong here looking at specs, but my heads valves are at 2.20 intake and 1.8 for the exhaust valve. The AFR's are 2.02 and 1.6. Can you advise on this? I do reliaze these are aluminum instead of 100 ton/ea original 882 castings like I currently have.

 

If your considering heads then why not a mechanical roller cam also..and comparing your 882 to a set of AFR,s valves being the same or not!!! It,s all about flow and port design valve sizing in this instance is really irrelevant.AFR,s or most any other after market head (hell even the Vortec,s) will beat them hands down...

 

I see...yea...Not to polished on my knowledge of head work...But they are a nice penny $1500/pair! Would any other mods be needed to go along with these heads? You mentioned the cam, what would you suggest?

 

I don't know who did your heads, but there is no way to fit 2.20 intake and 1.8 exhaust valves into an 882 head. They would hit the cylinder walls when opened especially in a 4" stock bore. Even if the didn't hit the walls, they would be so close that they would be effectively shrouded and flow would actually decrease.

Like slapshot said, valve size is really irrelevant. Check out flow specs and port design. The AFR's are generations beyond the old 882 castings. I have Edelbrock Performer RPM heads and could probably pick up 20-30 hp by just switching to the AFR's.

The 882's will flow a little over 200 cfm, maybe 206. The AFR 180's will flow about 270 cfm, basically almost 30% more air. That means HP.

 

I'm kind of suprised no one else said this but your intake is holding you back.

I would get an RPM Air-Gap and a 2400 stall.

That combination should help.

 

Not with his current cam. I had the same cam in my L48 before I went to a roller. The Crane 270 only has about 216 @.050 lift. Peak RPM will be about 5500 rpm. That is why I would go for the AFR 180's vice a bigger head.

 

Hey Bronze, you think that would be a noticeable difference?

 

the only way i can see making a cold-air intake is on the passenger side behind the gills.

run a HUGE pipe from the carburator to the passenger side gill area, and in that area create a sheetmetal airbox that contains a K&N cone filter and sucks air from below. so the sheetmetal behind the passenger side front tire has to be removed.

I would love to do this on my '69 except that it would look like an abortion.

it starts with a product like this: http://www.atlanticspeed.com/product...6&idcategory=0

and also some sheetmetal and some pipe and elbows