67 GTX

When the 375 hp 440's came out, you were told to give to gas with an octane of 103. Thanks to today's bad gas, we only have 93 as the highest octane. My 440 for some reason never pings (I heard that this is a problem with the old high compression engines.) Does anyone know why? Does it have to do with flat top pistons and headers?

67 GTX

i have advanced the timing to 7.5 advanced
stock it was at 5

Commando

What year is the engine? As I have been thinking about the timing in my 440, and what I should set it at.

67 GTX

it is a stock 67 engine with the 915 heads

67 GTX

so my compression is now somewhere around the stock 10.1:1

Commando

Ok, sounds good. I will definitely consider your timing when I get to that part of the project.

67 GTX

ok, good luck putting the pistons back in
if you have trouble, you can ask me, because I had to put the tool on them that tightens the compression rings, and once I got the piston sitting in the cylinder, I pushed it in with the wooden handle on the hammer. Then, they fall right in.

67 GTX

i was really surprised today
i got 15mpg with the car with mix city and highway
projected, city: 12-13mpg
highway: 17-18mpg
not nad for a 440 with 3.54 gears
i was just hoping to get near 12 mpg today!

challenger

Hey 67 have you thought about running e-85 with 105 octane i run it in mine and some people cry when you say e85 but to me its a great fuel , have you got a spacer under your carb as that sometimes helps with the pinging ,,, do you have adjustable rockers on them 67 heads ?

67 GTX

i have adjustable rockers
where would you find this e85 gas?
the wierd thing is that the car never pings

rr69half6bbl

mopar action did an article on the ping issue. Anything under 9-1 can run on cheap stuff, the squeeze on them isnt that bad, when you have a high comp. motor, the btu rate of the fuel isnt high enough to fully burn the charge ,therefore causing the ping issue. I run 7 gal. of 104 and fill the rest of the tank w/ 93 on every fill up and run the timing at 14 advanced . My 440`s 10.3-1. teh motor loves it. no smoke, no ping. just the alcohol smell.

Commando

I am guessing that with the Speed Pro (Sealed Power) pistons I am going to use with the Edelbrock heads (84cc) I will be getting it to about 8:1 - 8.5:1, and I put 93 in it anyways so I should be good then, right?

78D200

more than enough. you can probably get away with running 91 octane actually.

Commando

I think when I finish I will run the 93 just to be safe, until I get a better estimate on the actual compression ratio.

Or if someone would be kind enough to give me a second opinion on the ratio. I have a stock block, so the bore is 4.32, I plan on using these pistons: http://store.summitracing.com/partde...F&autoview=sku , these cylinder heads (84cc ones): http://www.edelbrock.com/automotive_...r_bb_rpm.shtml and the gasket I have I got in one of those MR. Gasket rebuild kits from Summit I think its this one: http://store.summitracing.com/partde...5&autoview=sku

My calculations now that I look at them are about 8.8:1, but I did a lot of guessing, due to my inexperience in this matter.

78D200

I wouldn't use the 84cc heads if you plan on running 93 octane (just my optinion tho). Since you are going to be running the good stuff, get the 88cc heads, bump up your compression a little, you'll be more happy.

67 GTX

but my car never pings with just premium 93 octane gas

Commando

I will run the calculation again tomorrow with the other heads and see what it says, also I'll see if there is a change in price.

challenger

hey 67 have you tried just to run the 89 oct in your car , if it seems to run fine i would just use that and if not go up a notch and run the VR1 valvoline oil in the motor , it has some of the most zinc in it , have you checked your timing chain to see if its not streatched because you dont want to advance the timing to much if you can help it , what carb are you running ?

Commando

Ran the calc again and got 8.55:1, thought it would have gone the other direction, will check out price now.

Will there be a difference in efficiencies with the mpg?

78D200

you might get a little more, like .5 - 1 mpg but I could be wrong, I am only human.

Commando

Oh ok, I was cleaning up the block today, looks like I will be sending it to the machine shop to have it bored out unless he can hone out the rust. While its there I am going to get some other stuff done, so I think I will have the engine running on the threshold of 93 octane gas.

Commando

Back to the timing, I have the engine in the machine shop soon to be finished, and am thinking if I should mess with the timing on the cam. Is the 12 o'clock for both the cam and crank 0 degrees, or is it 5 degrees like you mentioned above? Just looking for an idea on what to do if anything.

For reference I have a 1977 440 bored .30 over, Edelbrock performer cam, sealed power flat top pistons, steel crank, and headers. Will be putting aluminum heads on it and Edelbrock Performer intake as well as some other goodies.

67 GTX

i just set my cam to standard
it dont have a radical cam though, just a little more than the stock 67 one

Commando

Oh ok, I thought you may have done the advance at the cam, so would I be correct the 2.5 degrees you said would be at the distributor?

67 GTX

no, 7.5

Commando

oh ok, I meant after stock, so total 7.5 degrees.

67 GTX

yep