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Do you NEED an octane booster?
I have a 10.63:1 compression ratio, and run on 92 octane out of the pumps. I did a bit of cam timing tweaking, but that is all I needed, and never have a pinging problem. All I did was pull the cam 2* retarded to bleed off some DCR and that did the trick.
Higher octane effectively slows your combustion, so if you don’t NEED it, it can actually hurt performance…
Same here I have 11:1 compression and I do just fine on 92 octane. Which doesn’t mean anything because its all about the quench.
I just know my cars run better with more power when I run some racing fuel through them. Unfortunately I don’t have the expertise to fine tune my cars.
What are the specs of your motor?
In the ’68 GTO it had a complete valve job last summer, sorry I don’t know the details. There was a distributer problem in that it was frozen in one position. I know that was a big problem in trying to fine tune the car. I think I could probably run on 92 octane but it sure likes the 110. When I bought the car I was told it had a rebuilt engine with hardened seats. I found out last summer the seats weren’t hardened and that it needed a valve job. When they had rebuilt the engine they used a mish-mash of parts. I had alot of fun with it for 4.5 years before it needed that, so that’s not too bad.
The other is a ’69 Plymouth GTX. Its got a 440 with a 6-pack, 4 speed. The 3 carbs have been rebuilt and on and off about 10 times to get them to where they should be. Started it last weekend and the rear carb drips a little gas from around the bowl, hopefully that will take care of itself, otherwise we will be buying a new bowl.
Quote:In the ’68 GTO it had a complete valve job last summer, sorry I don’t know the details. There was a distributer problem in that it was frozen in one position. I know that was a big problem in trying to fine tune the car. I think I could probably run on 92 octane but it sure likes the 110. When I bought the car I was told it had a rebuilt engine with hardened seats. I found out last summer the seats weren’t hardened and that it needed a valve job. When they had rebuilt the engine they used a mish-mash of parts. I had alot of fun with it for 4.5 years before it needed that, so that’s not too bad.The other is a ’69 Plymouth GTX. Its got a 440 with a 6-pack, 4 speed. The 3 carbs have been rebuilt and on and off about 10 times to get them to where they should be. Started it last weekend and the rear carb drips a little gas from around the bowl, hopefully that will take care of itself, otherwise we will be buying a new bowl.
Are you have pinging issues if you try to run 92 octane? Sure any healthy V-8 will allways like more octane. Now with your 440 I would bet its a tuning issue unless the 440 has been built up at all. 6-packs are tricky to tune.
Quote:Same here I have 11:1 compression and I do just fine on 92 octane. Which doesn’t mean anything because its all about the quench.You got that right…lol
.040″ here, absolutely perfect quench for my 355. .025″ deck height, and .015″ shim head gaskets.
Quote:Quote:In the ’68 GTO it had a complete valve job last summer, sorry I don’t know the details. There was a distributer problem in that it was frozen in one position. I know that was a big problem in trying to fine tune the car. I think I could probably run on 92 octane but it sure likes the 110. When I bought the car I was told it had a rebuilt engine with hardened seats. I found out last summer the seats weren’t hardened and that it needed a valve job. When they had rebuilt the engine they used a mish-mash of parts. I had alot of fun with it for 4.5 years before it needed that, so that’s not too bad.The other is a ’69 Plymouth GTX. Its got a 440 with a 6-pack, 4 speed. The 3 carbs have been rebuilt and on and off about 10 times to get them to where they should be. Started it last weekend and the rear carb drips a little gas from around the bowl, hopefully that will take care of itself, otherwise we will be buying a new bowl.
Are you have pinging issues if you try to run 92 octane? Sure any healthy V-8 will allways like more octane. Now with your 440 I would bet its a tuning issue unless the 440 has been built up at all. 6-packs are tricky to tune.
The pinging issues in the GTO have pretty much gone away with the distriibutor being freed up. Never really had any pinging issues with the GTX.
The GTO seems to have more power running 4 to 5 gallons of racing fuel through each tank. With the GTX there has never been an issue with power, but it likes the racing fuel also. One thing I like about it is that it smells like corn syrup when you run some. When I buy it you can’t put it directly into the car, it has to go into a can first, then into the car. I would assume it must be that way all over.There are at least 2 places here to get it, and its remained stable at $4/gallon.
Quote:Quote:Quote:In the ’68 GTO it had a complete valve job last summer, sorry I don’t know the details. There was a distributer problem in that it was frozen in one position. I know that was a big problem in trying to fine tune the car. I think I could probably run on 92 octane but it sure likes the 110. When I bought the car I was told it had a rebuilt engine with hardened seats. I found out last summer the seats weren’t hardened and that it needed a valve job. When they had rebuilt the engine they used a mish-mash of parts. I had alot of fun with it for 4.5 years before it needed that, so that’s not too bad.The other is a ’69 Plymouth GTX. Its got a 440 with a 6-pack, 4 speed. The 3 carbs have been rebuilt and on and off about 10 times to get them to where they should be. Started it last weekend and the rear carb drips a little gas from around the bowl, hopefully that will take care of itself, otherwise we will be buying a new bowl.
Are you have pinging issues if you try to run 92 octane? Sure any healthy V-8 will allways like more octane. Now with your 440 I would bet its a tuning issue unless the 440 has been built up at all. 6-packs are tricky to tune.
The pinging issues in the GTO have pretty much gone away with the distriibutor being freed up. Never really had any pinging issues with the GTX.
The GTO seems to have more power running 4 to 5 gallons of racing fuel through each tank. With the GTX there has never been an issue with power, but it likes the racing fuel also. One thing I like about it is that it smells like corn syrup when you run some. When I buy it you can’t put it directly into the car, it has to go into a can first, then into the car. I would assume it must be that way all over.There are at least 2 places here to get it, and its remained stable at $4/gallon.
Ok I see where you coming from now!
Quote:Quote:Same here I have 11:1 compression and I do just fine on 92 octane. Which doesn’t mean anything because its all about the quench.You got that right…lol
.040″ here, absolutely perfect quench for my 355. .025″ deck height, and .015″ shim head gaskets.
Is that one of those thin cometic gaskets?
My block was zero decked to my flat top pistons and I am running a .039″ head gasket. Although I am not sure if thats how they figure out quech area. Doesn’t the quench area go up into the chamber some and down into the piston if you have dished pistons? Quench is one of those things I know some info about it but don’t understand it enough to to spec a good motor. So when I did my motor I went and talked to people that did know! thumbsup.gif
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