[Skippy597]

I know I've asked in the past and have gotten some great info. However I also just asked powell machine for a cam rec and custom grind as I am impressed by his knowledge on his YouTube videos. So here's my engine specs and the other cams I'm comparing it against. Just looking for a hot street machine and want 500hp+.

400 based
4.25 scat forged crank
6.8 scat H beam rods
Ross 4.150 20cc dish pistons
Speedmaster round ports cleaned up 72cc
KRE dual quad intake
2 X 650 AVS2
Approx 10.2:1 CR

Muncie M20

3.36 rear gear and 275/60r15 tires

Interested in your thoughts here

The cams:
Powell custom (claims it to be better torque and more responsive)
230/245 .618-.618 110+3

Comp grind (my original choice)
288/294, 236/242, .573/.594 112

Butler custom (claim it will make a little more torque but that's it)
239/247 @ 050 .623/.633 113 LSA

All lifts are with 1.65 rockers and hydraulic roller grinds

I think it's interesting that when I asked Butler for a custom cam rec they went bigger while Powell went less on the int duration. I'm not one to doubt or question him as he is far more knowledgeable than I and he stated that with my speed master heads being too small for my 460 that I don't need a bigger cam as it is in a way wasted.

[JLMounce]

That comp grind that is very close to the Old Faithful cam is almost always a great choice in these engines. It's hard to mess that up as a hot street engine with good manners.

I've run a 232/238 112 on as cast KRE heads in a +0.030 455 and that engine made great torque and power, but I always felt like I wanted a bit more cam. I currently run a 240/248 112 on a +0.040 455 with 310cfm KRE D-ports. This cam rocks. There's power everywhere and with the torque converter I run that stalls at about 3200 rpm behind the engine, traction is a real issue. With my setup, the driving manners are actually very good. There's enough stall to soak up any awkwardness below about 1400 rpm. If I was running a tight torque converter, or a manual transmission, it's possible there might be a slight amount of bucking around 1200 rpm in loaded high gear. Vacuum would be a concern if running power brakes.

The Butler custom grind will be somewhat similar, erring towards a little bit more manners and the 113 LSA is going to provide a bit more vacuum. That Comp grind though is likely a great compromise between street manners and performance. I think you're going to see between 500-530hp and around 550-570 torque out of that cam with your combination. It's will probably also be a bit easier to tune with your dual quad setup and will likely run power brakes.

Powell's cam in my eyes is too small for a stroker 400 and I don't believe your heads need that much exhaust duration split, especially if you're going to be running headers. I also think the 110LSA with 3 degrees of advance in it is going to plow a bunch of torque lower in the rev range and run out of steam early.

[steve25]

You need to get into the details deeper, as in comparing the difference between these Cams durations at .200” lift.

I agree with the last paragraph in the above that with those specs that cam is going to sign off on pretty fast above 5200 to 5400 due to your motors stroke more then overall CID.

[grivera]

Don't take this the wrong way but who do you trust more - PY Forum members or engine builders/cam designers?

[Dragncar]

It will be hard to not make 500+ HP with whatever you pick.

[64speed]

455 based 468 here. Edelbrock round ports with the Crower 60919 and 1.7 BBC rockers. Performer RPM intake. I don’t know what the exact HP and Torque rating is but it’s more than you could ever use on the street. Yes it’s out of steam at 5400 BUT at 5400 you are going so damn fast you can’t control it so..,

[Jay S]

The custom Bulter cam looks like it is a QXX profile. Do what ever you want, but power wise, it will out run those other cams everywhere.

They are all smaller cams than I mostly have. Unless you’re towing, extra tq mostly just makes it harder to get the car to hook up. I don’t know why Powell thought it needs more tq. The cam in this video is 245/[email protected]” 114 LSA with 3.23s and 275 drag radials. Below 40 mph takes a lot of back peddling in 1st gear. Generally helps to short shift it at below 5500 until it hooks up.

https://m.youtube.com/watch?v=HfaFWp...1vdG9yc3BvcnRz

[jhein]

I have the Comp cam that was your original choice with but with 1.5 rockers. Runs very strong. Nice idle. Pulls 15" vacuum. With street tires it's completely ridiculous. But if I drive it like a sane person it behaves very tame. No bucking or fussing.

[Skippy597]

Ok sounds like I'll stick with my original choice or actually probably Kauffman's version as it has slightly more lift on the intake side. I'm sure Powell has good reasoning for his cam recommendation, however seeing that many hear are happy with the 236/242 cam I think it's a good compromise. The butler custom choice I'm sure would make more power but if it's gonna loose it lower end drivability that takes it off the list for me. I don't want to be hating life if I hit traffic.

[Formulas]

There's Ridiculous speed then Ludacris speed and then there's Plaid.... I wanna go Plaid just once

[Jay S]

Originally Posted by jhein

I have the Comp cam that was your original choice with but with 1.5 rockers. Runs very strong. Nice idle. Pulls 15" vacuum. With street tires it's completely ridiculous. But if I drive it like a sane person it behaves very tame. No bucking or fussing.

The cam you have will have the most off idle power a best vacuum of the 3 cams.

[Skippy597]

I can't handle the plaid

[ponjohn]

What I like on the powell grind is the wide spread between intake and Ex duration.

There is another member on the forumn, cough cough Lee cough, that follows this same strategy.

Did you provide Powell with flow numbers, csa and any ther specs?

[Skippy597]

Here is a couple quotes from Powell about why he chose what he did.


"My ivc is 4 d earlier for better dynamic comp, my evc is 5.5 later for more cyl evac, and i have 3.5 more OL which the cyl head needs as its way to small for the engine"

"Those cubic inches require 330cfm to make peak power at 5500rpm, you have 289.................., it's just math, the more cfm you have the less cam you need to do the same job"

He is definitely intelligent on engine building and cam specs so I'm not doubting him on his reasoning. He also did really well in weingartners cam challenge on YouTube.

I did provide with the flow numbers for the factory as cast head and informed him that mine will be a little better as I'm cleaning mine and a good valve job.

[Geoff]

I love it when they their cam will 'make more tq'.
More tq....compared to what?

[Jay S]

I like Powell a lot, but it is a pretty big assumption that 330 cfm is needed for turning 5500 with 460 CID. That is more of a modern engine family way thinking for an LS, Gen 3 Hemi, or some Ford’s. Even on a modern engine platform it is a big stretch, that is well over 130 % VE.

One of the guys on PY recently dynoed in at 490 HP@5100 with his 461 Pontiac with 242 CFM D ports and 560+ lbs of tq. It was a Bullet HR and 236/[email protected]”. With a single plane intake, more carb and bigger headers, it even would have made peak power at close to 5500 with those 242 cfm heads.

[Skippy597]

Thanks Jay, that's a good point. I just got done reading his Dyno thread and it is for sure a stout engine. I would assume with a nearly identical cam, and the rest of my setup I should probably be right where I want to be, maybe 520-530 @ 5300 ish. It's nice to bench race but even nicer to see real world results.

[scott70]

Originally Posted by Jay S

I like Powell a lot, but it is a pretty big assumption that 330 cfm is needed for turning 5500 with 460 CID. That is more of a modern engine family way thinking for an LS, Gen 3 Hemi, or some Ford’s. Even on a modern engine platform it is a big stretch, that is well over 130 % VE.

One of the guys on PY recently dynoed in at 490 HP@5100 with his 461 Pontiac with 242 CFM D ports and 560+ lbs of tq. It was a Bullet HR and 236/[email protected]”. With a single plane intake, more carb and bigger headers, it even would have made peak power at close to 5500 with those 242 cfm heads.

Very similar to mine. 254cfm iron heads, iron intake, qjet, 232/241 @ 050 hft,,112 LS. 491 hp at 5200, 570 trq at 3100 rpms.

[mgarblik]

I also enjoy the Powell Machine videos, his general attitude and the skills he displays. His knowledge base is skewed toward the LS platform, not to say he isn't a fine machinist. His recommended cam may work as advertised, but every time I try a 110 or tighter LSA, I end up regretting it in a Pontiac street application. Not being a cam designer, I can't explain why, but the wider LSA cams with identical or similar profiles always seem to have better street manners and generally better overall results on the dyno. This is not the case with other platform engines consistently like a Pontiac. Did you happen to talk to Tim Goolsby @ Ultradyne/Bullet for a recommendation? He has over 30 years experience and seems to really know the characteristics of Pontiac V-8's. I know an engine is just an air pump and the cam doesn't know what engine it's going into. But that's really not the whole picture.

[Skip Fix]

The UD HFT 239/247 @0.050 in my 455 in the 78 is on a 112. The new SR Tim ground for me(UD lobes form Bullet) for a freshen up of a 400 for the street is on a 112. And he said he usually likes 110 or tighter but was what we felt would work on this.