Hello, I am trying to find out if I can use 100 Ron fuel with around 11-1 compression in my 545ci, Heads are the Edelbrock 61649 with 75cc chambers, As I have looked at two stroker pistons for the 545ci one has a 22cc step dish which with give around 11-1 compression the other is a flat top that will give 12-5-1, I know with the 12-5-1 compression I will have to use racing fuel so for now I am leaning towards the 11-1 compression piston hopefully using 100 ron fuel with a adative octane booster if needed, Thanks..Jamie - Australia.

 

I think... in a word ....Yes

I mix 91 Octane with aircraft 110 octane every once in a while as a treat for my 429

 

are you still using that motorsports cam? if so its got enough duration it should be ok, but you may have to play with the timing a bit.

 

Hello darrin1999, No I will not be using that Ford Racing cam, its long gone-sold, I am looking at two camshafts by Doug Herbert, one is a Solid with 690/690 lift and 274/274 duration, the other is a Solid Roller with 700/710 lift and 264/274 duration, both cams RPM range is 3'500 to 7'500 but will come come to 3'000 to 7'000 as I am adding nearly 100 cubic inches. BP are releasing a new 100 octane fuel very soon down here so I will give it a try, Thanks Jamie.

 

id definitely go the solid roller, that solid flat tappet cam is a chevy grind, not a ford grind. note the equal intake and exhaust lift and duration- thats the mark of a chevy grind. ford grinds have more lift and/or duration on the exhaust to compensate for the lower flowing exhaust ports. oh, and with that kind of duration and rpm range youll definitely be fine with 11-1 on the 100 research octane gas assuming you have your quench/squish set up properly and the timing set properly
oh, and one more thing... the rpm range may drop a little more than that... id say around 2850-6900

 

Hello darrin1999, would I be better of finding a cam with a 4'000 RPM starting range as it will come down to say 3'300 to 3'500 in the RPM range in my rebuild,As that way it will match the Victor intake. The pistons I will be using will give the engine a compression ratio of 11-5-1 , and yes I think I will go with a roller cam and lifters from Doug Herbert, Thanks Jamie.

 

if you can, you should find out the motor octane rating as well as the research octane... the average will probably be around 93 or 94... which is pump premium in the east. you should be good on 11.5-1 with the roller cam and that octane with conservative timing.

 

If the quench design is anything like my Cleveland (stock 11:1), I have always run pump gas, and even gone with regular once or twice, without any ping at all... Make any sense to you? Me neither! lol But, I do know that a quench chamber is better to thwart detonation than an open chamber head.

If the country turns into a Mad Max film, you might want to see that you can run pump gas. LOL

 

Guys, What about the cam range ? should I look at cams that have a 4'000 Starting point as it will come come to say 3'400 to match the Victor intake, or a 3'500 starting point that will come down to say 2'900 ??????

 

You have to decide what range you want all your power. For a heavy vehicle, you likely want power up to 5500 with an emphasis of low rpm torque, but for drag racing, you will want more engine speed, but you will need some high ratio gears to match.
What is your intended purpose? With that many cubes, it would be a drag racer or an extreme street racer if I were to guess...