Every dollar you spend on getting the compression up, you will get back in fuel savings, and it won't take long.
A big displacement low Dcr engine sucks gas big time,and that gas costs more money almost every day.
IMO,Your compression should be priority #1.
Give up the MSD, or the shiney new 4bbl carb, or the fancy intake. But don't give up a point of Dcr. Try not to give up even a half a point of Dcr.
You will have more fun with a small cam and a hi Dcr, than a low Dcr,big-cam,gas hog.
Put a 2bbl on it if you have to, but don't skimp the compression, please.
Even if you just zero deck it and kept those pistons, you might be up to 10.1 Scr. This would allow you to run a cam with a 62* ICA. to get a Dcr of 8.2@165psi. This works out to a cam of 272/110.This would be a very torquey engine.And a 272 cam when well tuned, can make excellent fuel mileage, and I think should top 400 hp.
At 8.2Dcr, the bottom end will be crazy strong, with a nice fat midrange, perfect for a streeter. I bet you can run this with the factory TC and 3.23s.
But if you leave the compression down at 9.12, and run that same cam with the 62*ICA, then the Dcr falls to 7.4@145psi. Well firstly, you will need a bigger TC, cuz at 145 psi, the bottom end is sick. You may not be happy with the 3.23s either so in go the 3.55s. This is a triple whammy to fuel consumption. And a triple whammy to your wallet.
The cost alone of the TC and installed 3.55s will far exceed the cost of the zero decking,even if you have to bore it and put higher compression pistons in it.
And then there is the fuel consumption thing. That low compression engine, with the big TC and the 3.55s, will remind you at every fill up, that it is a gas hog.
Please consider bumping up the compression.You will never be sorry.
I tell you what, as a streeter and with 3.23s, that engine won't even be able to use the secondaries until near 30 mph. And they (the secondaries) are only good for maybe 35/40 hp in this engine. And the engine won't make that power instantly at 30 mph, it will actually have to spin to past 60 mph to get the full power of those secondaries.
And if you put skinny enough tires on it to blow them away every time you take off, that is not the fast way down the road either.
If I was too broke to bump the compression AND buy a 4bbl induction, I would choose compression in a heartbeat. You can always add a 4bbl down the road somewhere; quick and easy.
I would even leave the 2bbl cam in there if I was that broke. (unless the Dcr was so high as to drive the engine into detonation). Detonation is to be avoided at all costs.
I know some other guys on here, preach a point of Scr is not worth chasing, but IMHO, a streeter cannot afford to give it up. Probably 90% of your driving will be at part throttle, in the low effective-compression zone. And if the Scr/Dcr is not there, you will have to drive deeper into the carb than you need to, and deeper in the carb is always burning more gas.
I'd like to give you some numbers but they would be pure speculation.
Ok you twisted my arm.I cry Uncle!
All calculations are with 27" tires.
The gear swap from 3.23s to 3.55s will cost you about 5% hiway fuel mileage. Thats about 1 mpg.
The TC swap from 2200 to 3000, will also cost you hiway mileage.The 3.23s will hit 65=2608rpm at zero slip, while the 3.55s=2867 rpm. The 2200 will probably be fully locked up, while the 3000 will be slipping a lot. Slipping makes heat, and burns excessive gas. I'll guess another 1.5mpg.
But that same 3000TC will also cost you gas every time you step on it, leaving a stop! Every single time. I'll guess another 2 mpgs.
The lower compression isn't much. Going from 9.12 to 10.2, is probably only 2% mileage penalty so I'll guess .5 mpg, in steady state use. But again, that low compression will cost you gas every time you step on the pedal to increase your speed; not just from a stop, but all the time.
>So, lets add this up.
First; steady state. We have the gears @1mpg, the TC @ 1.5, and the compression @ .5, for a total of 3 mpgs.
Next, city mileage. I'm gonna pick a number from thin air, and say Hi-stall combo is gonna cost you 5 mpgs around town.
Next Lets say you drive it for 6 months a year and average 1000 miles a month. That would total 6000miles of operation,annually.
>Lets say 85% is torquing around and just 15% is steady state.
So 85% of 6000 is 5100miles. Lets say the hi-compression combo was capable of 15mpgUS . Then;5100/15=340gallons.
And the lo-C combo loses 6mpg so;5100/9=567 gallons.
That is an extra cost of 567 less 340=227 gallons.
Now;steady state. We have 900 miles left.
Lets say the H-C combo goes 20 on the hiway; 900/20=45 gallons. And the lowC combo loses 3mpg so 900/17=53 gallons. The low-C combo thus costs you another 8 gallons.
The total thus is a loss of 227+8=235 gallons in one summer!.
So what's the cost of a gallon of gas in your area? Is it $3.50?
Well that is a loss of 3.5 x 235=$822 in the first summer. What if next summer the cost is $4.00 per gallon? That is another loss of $940. What if the summer after that it goes to $4.5? Another $1058 lost. So in three summers, you have spent nearly $2820 extra on fuel alone.
Adding that loss, plus the TC, plus the 3.55s installed, There is your triple whammy.
Keep in mind I guessed at all, that's ALL the numbers, and this exercise is pure speculation. Try not to look at the numbers as absolute. But rather look at the end result. I tried to be fair with them, but it could be a lot worse.
Hi-compression, no matter how you get it, should be looking pretty attractive by now.
>Sorry, I have to add;At the rate of 6000 miles per summer, that engine should last 20 years. But let's say it only makes it to 16 years. And let's say the cost of the lost fuel averages out to $940 per year;940 x 16=$15,040 lost to the low-C and the TC and the 3.55s. That's pretty conservative.
>Please remember, this is pure speculation.
I also have to add
My little 367 made it to 16 years, when I parked the car,not because the engine was done, but because the body is rotting. That engine will be 18 this September, and if I had another body, I would drop that engine in,change the oil, and d-r-i-v-e it! I built it to 10.9Scr, installed a 276/286/110 cam and with OOTB Eddies burn 87E10. I figure I saved about $70million in those 16 years,lol
