general sense of the state of my engine?

[H555]

need some opinions. we've got a 66 mustang, 200 ci. odometer says 74K miles which I've assumed is at least 174K miles. it drives ok, still messing with the choke tho.the car's had some mild body damage, the interior, while old and discolored isn't worn thru. seat belts also look pretty good. I know who's owned it for about the last 12 years, at one point it was really a little old lady. ball joints and tie rods ends had to be replaced recently, also put in a FR 16:1 steering box.

we're working through upgrades to the carb, ignition and exhaust. waiting for a pony carbs 1101 -V, spendy but mighty intriguing. then a 69 distributor with a pertronix ignitor system. needs new rocker arm assembly, the rocker arms will not move laterally at all and oil only drips from rockers for cyl 4,5,6. did a compression check and got 135# for #1 and #2 and 150# to 155# for 3 - 6. didn't squirt oil into the cylinders to see what that did for compression. top end isn't gunked up, the inside of the valve cover had a mild amount of cooked on stuff but no sludge. vacuum flutters slightly at 18#. valve cover has been repainted (didn't quite match).

the valve springs are clearly green so I'm thinking either this had been rebuilt at some point in the past or, is it possible that those are original miles?

I had been planning on tearing the engine down in the winter but now may hold off and do the body work. of course a rebuild would mean decking the block, high compression pistons, balancing, boring. moderate head work, porting, bigger valves, 3 angle valve job, maybe mods to the intake log or .... if money fell in my lap, the new classicinlines head....I can't help myself.

so here's the questions, in order of priority. should I be concerned with a 20# difference in compression for now? Is there any reason why #1 and #2 would be lower than the others (I mean like a design reason, not bad valves etc. I know the other reasons compression can be low)

would the original springs have been green in color? thanks for helping me prioritize our work. we're just finishing up a 3 year 65 barracuda project that was supposed to be 6 months and $4K. it's 3 years and $12K now... but it's totaly redone, ground up with a race prepped drive train. and yes I do always look for the next improvement I can make in anything, it's a character flaw... ;<)

 

[addo]

The motor's close enough. Do the wet test, diarise the numbers and get into the bodywork. That's locking in better value for your time expenditure.

 

[Bort62]

There is nothing lamer than a hot motor in a beat car.

Fix the car first, and the motor second.

Of course, I'm hardly one to talk.

 

[mugsy]

Just remember: opinions are like a**holes; everyone has one and they all stink!

So you're asking for our opinion :roll:

Those numbers sound very familiar, very close to my engine prior to a rebuild. When I tore mine down I discovered that the PO had installed a newer composite head gasket (at 0.040 inches thick) versus the stock steel shim (about 0.025 inch) head gasket. After measuring the gasket thickness, the deck height and combustion chamber volume the engine's compression ratio was in the 7.X to 1. Not good. I'd bet you're in there too.

Anyway, if you like the performance and gas milage of the car leave the engine alone. You could always remove the cylinder head, get a valve job and mill the head to restore the compression. Just mill the head enough but leave enough volume for the decking and flat top pistons in the future. By removing the head you can check the cylinders and see what condition the block/bores are in. A head gasket kit will not set you back tons of dough.

As for body work versus engine work, I am of the school that thinks who cares how good it looks, if the damn thing doesn't run or belches smoke out the tail pipe or shakes or can't even get out of its own way, then THAT is pretty lame.

 

[mceachrw]

make sure pony carbs plugs the scv for the 69 dizzy.

 

[jahearne]

20 lbs between adjacent cylinders might be too small to worry about, but it could mean bad head gasket and may explain the slight tick in vacuum readings.