I'm to the point in my project of reinstalling lines, hoses, wiring, etc. and need some tech advice.

First...went to install new spark plugs. Got the AC Delco R45TS plugs that my motor calls for and didn't even think about header clearance...they're not gonna work. Any suggestions on good plugs that are short enough to give me the clearance needed?

Second...went from stock (emmision and vacuum lines everywhere!) to a bare bones high performance motor. What do I still need besides power brake and distributor vac lines?

Third...another vacuum question. I've got the vacuum reserve canister that mounts in the forward drivers side of the engine bay. It has two fittings, one marked 'carb' and the other marked 'tank'. I initially thought it had to do with power brakes but now wonder if it has to do with the fuel tank? What purpose does this thing serve and do I still need it?

Last question...at least for now! Rear drivers side head has a threaded sensor with two blade type electrical connectors. Not sure what this originaly hooked up to and not sure if I still need it. Info that may or may not help: I do still have the temp sensor that mounts in the head near the spark plugs and I've gone to all Auto Meter mechanical gauges in a Covans inst. panel.

Might be dumb questions but....you don't know what you don't know.

Thanks in advance for any assistance.

 

First: Go to the parts store and ask for header plugs. They are a little shorter, hopefully enough to give you clearance. Problem is this, will there be adequate clearance for the spark plug boots? It may be a tough pill to swallow but in the long run you might be better off replacing the headers. Whatever heads you have there are headers built to fit, even angle plug heads.

Vacuum Lines: By bare bones, do you mean no heater? The heater controls need vacuum to operate.

Reserve Canister: The can you refer to is actually part of the emissions system. It is a charcoal can designed to trap fuel vapors and then feed them to the engine. It is not needed for the car to operate, your state laws may say different.

Sensor: Sounds like the electrical sender you have may be a knock sensor, totally useless.

 

Great answers JRs72RS. I might add..What type of engine did you put in? Aluminum heads are often angled plug heads, I have them in my 70 and hooker super comp headers were the only ones that fit (tried 3 sets) they can be a REAL headache. Also, if you put in a "high enough" high performance engine inthat has a fairlybig cam, you may not have enough vacuum to run anything, at least not at under 1500 or so RPM, Im working out those problems right now on my 68 lemans...

 

As always...friendly and helpful advice. I really do appreciate it!

Okay...

The motor is a Blueprint 355 with an Edelbrock RPM Performer top end kit (1500-6500 RPM range). Should make about 410 hp & 408 lb torque. Compression works out to be 9.39. The heads are straight plug and according to Edelbrock the cam should give me 10-12 inch of vacuum at idle. The headers are Dynatech Musclemaxx.

Oh ya...I've installed a Vintage Air system (about 80% installed) and don't believe I require vacuum for that...supposed to be 'fly by wire'.

Vacuum for brakes and distributor only? And do I have adequate vacuum under 1500 RPM?

I didn't go cheap on the headers and really hope they work. I think I just brain farted buying the OE plugs. The original motor had some cheap headers with slightly shorter Delco plugs and everything fit fine.

With shorter plugs, do I still gap them to GM specs for a 77?

Thanks again for the help!

 

10-12 inches of vacuum is marginal for power brakes. You should be alright as long as you do not get into a situation at a light and pumping the brakes. It will also depend on the diameter of the booster.

If you have the newer version of the Vintage Air, it should have electric actuators.

On the headers I wish you the best. It is best to really question the crap out of a manufacturer before you shell out money for headers. So far I have not had to use header plugs on any of my cars. It is also best to stick with the old established header builders, too many Johnny-come-lately builders only want your money, the do not think about the small details like spark plug clearance. One part fits all type of mentality.

Spark plug gap depends on your ignition system. Assuming you have an electronic system with adequate spark, gap at .045.

 

Thanks again.

The only thing more important to me than having a strong motor is the ability to stop! Should I consider a vucuum resevoir? I could easily mount it where the tank vapor canister used to be. Summit carries a reasonbly priced one. What do you think?

 

I would wait until you can drive the car. I would not trust the vacuum rating from Edelbrock, it is based on testing with THEIR engines and theoretical conversion to what you have. We have recently built a couple of cars without a booster. We did this with the guidance of Wilwood. I was skeptical at first but quite comfortable with the results. One was a full bodied 57 Chev with 700+ hp and 20" wheels, it stops great. There are ways to have good pedal without a booster. Think about a complete upgrade of the system, especially if you are going to use larger wheel/tires. Most people do not consider unsprung weight when building their car. Large wheel/tire combinations may require four wheel discs and/or larger calipers.

 

Interesting. I guess that without the booster vacuum becomes a non-issue?

I do plan to upgrade the brakes and suspension...probably after I'm back on the road for awhile and get a feel for the car again. For now I'm keeping 15" wheels...trying to maintain an early 80's look (high school car). I'm on the fence about going with a rear disk conversion or the 'police option' kit with 11" drums and kevlar pads. The drum assy would be easier (pre-assembled on backing plate) but the prices have recently gone up bringing them closer in price to the cheaper disc coversion kits (like Summits). What's your opinion on those two options?

 

I have never tried the oversize drum kits. The system we are installing is the Wilwood superlite series. The calipers are four piston and we also use the Wilwood master cylinder. Total cost installed with 13 inch drilled/slotted rotors, all new lines and stainless braid is around $4000. Wilwood also has some kits that are lower in price, although I am not familiar with them.

The larger diameter of the rotors and the fact that the calipers are four piston are what makes the system workable without a booster. I see Summit offers a kit from Wilwood with four piston rotors and 12.19 dia rotors for $750 (WIL-140-8582D). That would get the price down to around $1850 for parts (including a rear kit, Wilwood polished 7/8 inch master & adjustable prop valve). Remember, to gain more brake pressure, use a smaller bore master, factory masters are larger bore.

 

Cool. I didn't know that about stock master cylinders. Thanks again...I really appreciate the info and advice.