Thread: Building a new motor

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lets back up a little to your 327 again, what was the compression readings dry and wet (after a squirt of oil in the cylinder)? How long did the motor set without running?

The motor has been started regulary. I started the engine and got it up to operating temp. I then turned the fuel pump off, had my wife hold throttle until the middle 2 barrel was open and proceeded with my compression checks. I don't have all the numbers in front of me(I'm at work) but I remember they ranged from 125 to 145.

Did you test it a second time with a squirt of oil in each cylinder (wet test)? The oil will tell you if it is rings or valves. The oil momentarily seals around the rings and will raise compression if the rings are worn. If the compression does not increase with the oil, back the rocker arm nuts off 1 turn and try again. If the compression increases with the rockers backed off, adjust the valves and try again. It may just be a combination of small things causing the troubles. Do all of your compression tests with throttle wide open and all plugs removed and crank through a minimum of 5 or more compression cycles on each cylinder.
JMHO, there is nothing alarming with 145 psi compression test readings in a street motor and if you have two cylinder adjacent each other low, that is a sign of a blown head gasket.
Don't give up the ghost on the 327 yet, you can have just as much fun testing and trouble shooting as you can re-building a motor. And, the testing skills will pay big dividends in the long run.
Also, JMHO, but, MSD ignition and/or a new distributor will not increase compression. The MSD will help fire fouled plugs though.

I know it doesn't help with compression but I know the 3 deuces are part of the problem. I'm hoping a hotter ignition will help with that problem. The compression is something I will check like you recommended.

What are the carbs doing?
http://www.reds-headers.com/Demon98Manual.pdf

They are very sensitive to weather it seems. Some days it runs pretty good and others it runs like a corn planter. I have rebuilt them and adjusted mixture screw like recommeded. I think there isn't enough spark to burn the fuel. Anyhow no matter what I think, I will find out when I put the new MSD in it. I will perform the wet test and find out results. If they are the same then I will pull a head off and check.

What do the plugs look like?

Plugs look ok. a little wet from fuel.

The plugs will tell all, what color is the insulator, where is the heat band on the strap, what does the thread end look like? Does your center carb have a choke? What is your timing set at? When you rebuilt the carbs did you set the throttle blades to the transition slot? What is your idle vacuum? Are any ignition wires showing signs of arching?
These are all things you need to know before moving any further. Your timing may need more initial and your carbs may need finer adjustments. In the link I provided above, the trouble shooting section covers what you may need to do to the carbs.
And again, I'll reiterate the need for a thorough tune up first. While the MSD distributor is probably a good choice and will improve performance, if your on a budget stop guessing and refine your tune up and trouble shooting skills. In most cases inexpensive meters and gauges will save you a bundle. Plus the learning can be very enjoyable.

Yes you are right. I need a full day to go thru everything. I finally found the guy who built the motor and talked to him. He told me that the motor came out of a 67 chevelle ss. He said it was a 327/360hp? I think he is full of crap. They didn't offer the 327/360 that year. He also said it was the High compression motor. Im basically where I was before I talked to him. Not really sure what I trust. He did say that the motor had less than 1000 miles on it when my dad got it from him. I would suspect the motor has about 15K on it if thats true. I also learned that the rear is a chevy...not a 9". he told me I can back up about 10" and it would hook possi. Never heard that before either. When I put the MSD in it I will go thru the things you recommended.

It sounds like he has no clue or is some kind of bs artist. I would not trust anything he said.

Originally Posted by sefrayser

he told me I can back up about 10" and it would hook possi.

Around 1965 chevy had a 1/2 ton (maybe 3/4 ton as well) optional posi traction rear end that they advertised applying the parking brake slightly would lock it up, maybe he has confused it (we used to have to back up ten feet or so back then to disengage the early automatic 4x4 hubs). And, most likely he has also confused the 360hp for the L79 350hp, which was a very potent 327 for its time. Though it was a hydraulic cam (one of the first factory high performance hydraulic cams), it would scare the heck out of most of the competion back then. And yes, that motor was high compression, 11-1 if I recall correctly. Don't be fooled by the compression test numbers, you can not tell compression ratio by cylinder psi.
Honestly, tune it up, if you're worried, run some octane booster and substitute lead additives in your fuel. Drive the heck out of it and enjoy! Then look forward to your next challenges with it as they can be just as much fun as driving....

Ok here are my number with the dry test.
#1 165
#2 160
#3 150
#4 165
#5 145
#6 135
#7 140
#8 150
That was with #1 being driver front and #2 passenger front, etc. I also pulled the valve covers off and found out I have 291 double hump heads on it. I don't know if they are 194 or 202 valves. Should I perform the wet test? I also looked at the plugs close and they are black.

Looks like you may have a little carbon build up. Sometimes you can open the spark plug gap (.050 - .060) and give it a good run down the freeway to clean it out, then run the test again. I would expect to see numbers closer to 145 once the carbon is out.

With those numbers I think I would be looking at getting the carbs set right, running idle & mid-range off of the middle one and the outer two coming in for upper mid-range into WOT and run it for a while. Seems to me that it's just been sitting for a while, and needs some play time. Be sure to run a good oil, like Brad Penn's to protect the flat tappet cam.