duster3

Hi guys,

Newbie question here but I have a 73' Duster with a 68' 340 in it. 3.55 gearing.

My car has a 68' resoration rebuild w/cam, and edelbrock 600 carb.
I have the edelbrock performer intake for 318/360 currently slapped on there and just came across a free Performer RPM intake from a friend. I want a little more h/p (25-40) with a couple mods over the winter. I plan on jetting and tuning via dyno with o2 sensor.

Question is, *Should I put the Performer RPM intake on it or leave the current intake?? What are the bennifits/downfalls of either?

Im younger and trying to stumble my way through making my first "muscle" car more sweet! So ANY advice is greatly appreciated.

Thanks~Sean

bremereric

Probably not going to make that much of a differance. The intake runner ports will be the same cause the runners are much larger for after market heads or 360 heads. You therefore will have the same flow through the head runners and will not take advantage of the larger intake runners.

PK1

That is a great game plan! Tuning with an o2 is a must do.

You will see VERY large gains in that motor if you do a header AND intake swap. It is a great first step in waking the beast.

The RPM intake without headers wont do much but move the peaks up the rpm scale some.

I would not go out and buy the RPM if I had a performer on there, but if its free take it for sure, it will make more power in the mid upper rpms.. Then when you add headers it will make a big difference. Your carb is fine.

Coronet 500

My story on small block manifolds goes like this:
A real '68 4bbl manifold is one of the best OEM you can get.
Any 340/360 4bbl manifold works great.
The performer is not much gain to these but light aluminum which is a plus, put one on the truck because I had one.
The Perf RPM is OK but on a hotrod I'd go Air Gap but looking at bigger cam.

Free Performance RPM, are you kidding, I'd have it on there tomorrow, you bet. Time to get dirty, and like PK said open up exhaust and you'll definitely notice this improvement.

78D200

Any specs on the cam? I've always been a big believer in matching cam, intake and header RPM power band.

Dyno with an O2 sensor is a huge benefit too! that will really allow you to tune in that carb. However you decide to go, please post up all results!

Gorts 5th

i have seen those o2 gauges at summit if i where to get one where is the best place to install the o2 sensor left or right side header?
or would it be better in the cross over or H pipe?

Chryco Psycho

If you are using a dual plane intake both sides of the carb will be feeding into either side of the header so no advantage to either side , single plane is using both sides of the carb before entering the heads so basically the same result , I would not put it into an H pipe though

PK1

If you can weld or know a good muffler guy.. The best place to throw the bung is actually 3 places. For daily driving logging it goes in the X or H pipe or 24 inches after the collector for consistency. I throw a bung in each collector pipe to move it or trouble shoot problems.. if its a track car. Just plug the bung when not in use. This tool combined with a cheap IR heat gun can let you monitor individual cylinder conditions nicely.

I have installed a bunch but use Innovative and Zetronix myself.

Be careful.. Logging is addictive

Gorts 5th

sounds great i do suffer from a addictive character i might enjoy this logging please explain more.
How does the I R HEAT GUN work?

duster3

Thanks so much guys for the quick answers! I have decided to throw the RPM intake on tonight. I do have the stock Manifolds on the 340 and considered buying long tube headers. I used to have rack and pinion on it, I previously had some long tubes custom made to go around it. Ended up taking the rack and pinion out because the steering wheel linkage "kinda" bound up. End of story I pulled everything back out and went back to the "Stock" look. And all the car shows I go to people love the factory manifold look, hard to put headers back on with all the compliments lol

Anyway thanks again guys, my new favorite forum!!

Gorts 5th

Your welcome
pk1 where do you aim the I. R. heat gun?

78D200

Keep those long tube headers on the shorter side as that performer intake works best between idle-5500 RPM. The longer the tube, the higher the power band will be on teh RPM range. You might want to keep the stock manifolds on tehre for the time being (depending on how well they flow). Maybe look for a set of shorties?

Unless your on the track every weekend, I doubt you'll get over 5500 RPM but a few times.

PK1

IR gun can be used on the header to diagnose your fat or lean cylinders instead of an EGT meter or o2 on every primary pipe. Shade tree but effective.

A wide band down stream takes a picture of all cylinders. Putting an 02 and EGT on each pipe is expensive. So this bridges the gap.

Here is where an IR can help some

Example: Carbed small block single plane intake. Has a miss but otherwise runs good.

Cylinder Degrees
1 476
2 470
3 440
4 441
5 439
6 180
7 468
8 471

Fast idle set to 2000rpm and header temps recorded.
Cylinder 6 was firing but the spark was week with to much resistance in the wire. O2 read 11.4 ( not horrible but not good either) Wire changed and problem fixed. Temp rose to 445 and O2 reads 13.2. Don't pay too much attention to the degrees. Header coatings, cylinder head bleed thru, etc.. can do funny things. It is the consistency for all banks. The 180 doesn't fit. You can use a spray bottle with water too. No "hiss", no heat.

Look at the pattern if you can see it. The outer cylinders of 1,2,7 and 8 are hotter. The inner ones 3456 are cooler???? In this case 3456 were slightly fat. A "turtle" or "diverter" can be placed in the intake to move the air some. Pinch some from the longer runners or the shorter ones to dial in your temps.

I hope I explained that correctly. I was shown by an old circle track guy and they leave no power behind. I ain't smart enough to figure that stuff out on my own. But it has helped me over the years.

Gorts 5th

thank you... that helps i have a Milwaukee brand ir for construction i never thought of using it for temping the engine headers.