Hi Guys. I finally rebuilt a 1974 350 engine to replace my tired 307 and want it to look pretty much stock and also let the computer run it. I just pulled the 307 out and was comparing the two side by side and noticed the 350 heads aren't drilled to accomidate the air pipes. I am not sure what to do here. Can I eliminate the air pump and pipes and would the computer still run the car? Also if I do eliminate them,what electrical devices do I also have to remove. Any help would be appreciated. Thanx in advance Ed

 

The A.I.R. system won't set a code if you don't run it. The computer does control the diverter and air switching valves on the A.I.R. system, but there is no feedback to tell the computer if those parts are no longer there.

The bigger problem you have is the catalyst, if you are running one. The switching valve is used to switch the A.I.R. pump output from the exhaust ports to the converter. This extra air cools the cat and prevents meltdown in the event of a rich exhaust. I've managed to melt a cat by disconnecting the A.I.R. on a 307. If your carb is correctly jetted, this won't be a problem.

 

Interesting on the converter melt down. I personally would replace the cat, the original is very restrictive. I would do a timing chain and gaskets at minimum in the 350. Maybe a mild cam too.

 

Agreed. The cat that melted down was an aftermarket ;ow restriction honeycomb style.

 

Thanx Joe for the information. Just so you know I got a .010" and .010"crank, I had the bored .030" over, decked, pistons,rods resized, comp extreme cam, timing chain and gears, I redid the heads with a three angle valve job, a little bowl work, new springs,seals,keepers and locks. new seals etc. Also I used an Edelbrock performer intake. The 307 had 92,000 on it and wasn't worth a rebuild. hoping it will run ok with the computer. The converter is an aftermarket HP honeycomb and if it melts down I will gut it out.

 

What pistons did you use? The #8 heads will flow decent with bowl work. Sounds like a nice combo.

 

Thanx olds 307 and 403. The pistons I used are Silv-o-lites. They will work fine for what I want to do. Don't need to break the sound barrier. Just want to have a little fun driving to the Car Shows. When I feel the need for speed; I drive my 86 Custom Regal with a chevy small block 383 putting out about 435 HP. Gotta get back to work. Summers comming

 

"86 Custom Regal with a chevy small block 383 putting out about 435 HP."

Yeah, but those are smaller Chevy horses, so you need more of them to get the same result.

 

I get 7.5 to 1 compression with cast 24 cc dish and 0 deck and a clean up mill on your #8 heads. Which cam did you get? My stock 7.8 to 1 350 with a performer cam advanced 2 degrees should run mid 9's in the 1/8 this year. Getting my Cutlass ready too.

 

Mred355, did you measure your CR? I fear your CR is way down. I understand you're not building a fire-breather, but a 7:1 CR engine with bigger than stock cam might not get you the power you're looking for.

 

we will see. I was mainly after mid range

 

In don't think they will. I agree with the others, the compression ratio with that head/piston combo is going to be VERY low. Did you zero deck the block or just clean it up at .015? I hope I am wrong, but I think you going to be disappointed.