638 BBC --ALCOHOL OR 118 OXYGENATED FUEL ?????
 

HI GUYS , I HAVE A 638 BBC WITH BB4 CNC CONVENTIONAL HEADS , WITH TWO 1050 ULTRA HOLLEY DOMINATORS . IEM STILL IN THE PROCESS OF FINE TUNING THE MOTOR ON OXYGENATED FUEL [ $14 PER GALLON ] I WAS THINKING OF CHANGING OVER TO A COUPLE OF 1090 KING DEMONS ON ALCOHOL..I HAVE A 555 BBC ON MY NOVA WITH A RUPERT 1250 ALKY , AND IEM VERY HAPPY WITH IT . HAS ANYBODY HAD ANY EXPERIENCE RUNNING A BIG MOTOR , WELL 638 , ON ALCOHOL , I KNOW THAT ITS ALOT CHEAPER $ 3.75 PER GALLON ON ALKY ,,AND ALOT MORE TORQUE , I HEAR THAT HP DOEST PICK UP MUCH COMPARED TO OXYGENATED FUEL , SO THE ONLY ADVENTAGE WOULD BE THE PRICE AND THE TORQUE OFF THE LINE,,WHICH MIGHT BE USEFUL SINCE MY CAR WEIGHS 3100 LBS WITH ME IN IT , AND IT IS A BIG TIRE CAR 33-17-15 , SO IT WOULD HANDLE THE TORQUE . ANY THOUGHTS ABOUT THIS , THANKS IN ADVANCE FOR THE FEEDBACK. :D

I'm not even close to being and expert, but from what I've been told and researched a bit, alcohol is fine for big motors, but they are picky on the cam selection if you want it to run right. Not sure what needs to be done, but I do know it makes a pretty substantial difference if you have the right cam in it. I'd call Tracy Dennis at Sunset Racecraft, he's pretty sharp on this.

thank you mark , i will call him, and discuss my cam. thanks for the advice

638
 

Figure using twice as much alcohol as gas in your cost difference plus the cost of converting 2 carbs and the camshaft and ??. Do you really need to use the high price Oxygenated fuel?

thats true , i do need to figure out all the extra cost in converting , and then how much will i be saving in one year per gallon of fuel. if it gives me two tenths difference in the 1/4 mile or at least one thenth and a half , and my engine runs cooler , it might be worth it . but yea i need to seat down and figure out the expense. thanks for the advice :D

638
 

When I build an engine for alcohol, I use a gapless ring set to help minimize oil dilution and use a vacuum pump. When I get an engine to rebuild without those options, the cylinder walls and bearings often are prematurely worn out. Sometimes alcohol engines need internal maintenance sooner than gas engines if the tune up is rich?

Not trying to knock any fuel, just some things to look at.

Alcohol will work but from what I have seen from dyno numbers, gas is making better numbers in the bigger cubic inches. Personally, I would go alky but if you are looking to use it all up, gas may be the way to go.

thank you everybody for all the feedback. i appreciate it.

On a combo like that Gas most likely will be faster and easier. Sometimes these big engines get a miss but with the head your running I dont think that will be a issue. Call John Kyle @ APD, he does all the carbs for Sunset and has done a TON of alky cams and can help you out.