I’m starting to get parts together for my tornado 425. Stock bore 10.25 compression, I’ll be porting the big block B heads and filling the crossovers. Speedmaster single plane intake, using a quick fuel brawler 680 for now. 1:7 roller steel rockers. I’m torn between cams.

Both are comp cams extreme energy.
42-224-4
230@.050 and 236@.050 duration
.520” and .523” lift

42-225-4
240@.050 and 246@.050
.544 and .541 lift.

im currently running the smaller of the 2 in my build 350 and love it. It’s very well suited for that engine. I’m wondering if it would be too small or if I can just afford to go one size up or are the 1.7 rockers enough to justify the smaller cam. I’m running a 2004r and 3:23 posi rear at the moment. Obviously torque converter will have to be changed either way but that’s later on along with valve springs. Im looming for as much as I can get with my combo and it’s going to come down to the cam. Basically is the 225-4 too big?

 

I have a 66 425, B heads, single plane torker, stock bottom end, stock rockers (steel bridges). 1.7 rockers not sure about. Best cam I have run in this is a 292 comp cam hydraulic single pattern with a 850 demon. Combo just runs great, 3500 stall, 3.90 gear. car is 3650# ish... I personally think that second cam is too much for stock heads with light porting. I don't claim to know anything through. just trying to give a perspective on what has worked for me and what has not. I tried a .540 ish lift cam before and I swear the car was slower.

In my humble opinion with a 3:23 gear I would capitalize on the torque for a street car and dial the cam back to something around 230-230 .490@.050 or 224-230 .485@ .050.
In order to get the cam making power with the 244-244 .518@.050 with the 425 and iron heads I needed to step the gear up to a 3.90-4.33 and increase stall speed > 3000.

 

That was kind of my thinking. Although I am going for some top end rpm I don’t want to loose lot of bottom. As of now the car cruises at 100mph at 2500rpm with the torque converter locked so I don’t need a ton of top end. I over cammed my first car (327 impala) and it couldn’t get out of its own way but I didn’t care because I was 18 and it sounded cool at idle.

it’s good to hear from someone with the same setup though thank you!

 

 

That was a GREAT video!

 

Yeah, gives you a little more insight over what the manufacturers spec out.

 

So much wrong here, ie, all the valves AREN’T open at the same time, hence there isn’t anywhere near 4800# of pressure or whatever on the cam. Plus he doesn’t go into spring RATES etc.
Secondly, in general it’s usually best to lift at or just past the best flow number because the valve spends very little time at peak lift. Finally, he missed a bunch on his explanation of rpm range and lsa as well. I could go on and on but you get the idea.

 

I thought it was interesting how he showed flow numbers and wondered how many on here actually have had their heads on a flow bench. An "i[hone" and handwritten flow chart, you become "an authority". I guess thats why I call "my Olds engine Guru" to get real answers.