[Larry's 69]

I posted under Engine first, but thought there might be good feedback from here, also. Thanks.

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I finally got some specs on the cam in my 383 and am looking for some opinions on how it is in comparison to others/normal. It's a Compcam, 240/246 duration at 50, 507/510 lift. 2300-6500 RPM range. Now keep in mind, I'm challenged when it comes to this type of detail, and just learning. What other detail might you need to give me an opinion on set-up and how it should perform, etc. I'm apologizing in advance for any dumb questions or statements. Thanks.

[camaroman7d]

Not a dumb question at all. You might want to add the LSA (lobe seperation angle). I am assuming it's a hydraulic cam by the numbers you posted. Depending on the rest of your set-up this cam should be a decent performer. It might be a little heavy on the duration. Not a lot of lift for that much duration. Over all should be a decent street cam with a lot of rumble. If you like the way the car performs that's all that really matters.

You will need to list the vehicle weight, rear gear, tranny type, stall speed, intake system. and tire size to get a good feel if this cam is a good match for the combo or not.

[Larry's 69]

Thanks, Royce. Don't know the weight, it is hydraulic, 411 rearend, TH 350, 2800 stall, Edelbrock RPM, Mickey Thompson Sportman 29x15.50, BG Speed Demon. It has great thump at idle and goes like crazy. Thanks for the help.

[Silver69Camaro]

Sounds like it's decently matched with the combo, although it could use a tad more stall. Still good though.

I'm sure the cam has 110LDA, which should help with the midrange torque.

[Larry's 69]

With a combo like this, any guess about horsepower? I do plan to put it on a dyno. Thanks.

[greg moreira]

A 240 degree hydro cam will typically like roughly a 3500 stall speed converter(weight pending). As far as horsepower goes, what heads have you got and whats the compression ratio? The heads will heavily dictate how much power this thing can make. For example, that motor would be best run with a single plane intake and a 200-215cc cylinder head(like a victor junior and a 210cc AFR head) and about 10.5:1 comp or a little more for a streetcar. I beleive you can pull roughly 450 ponies or a little more out of that hydro camshaft and it surely has low 12 second, possibly high 11 second potential with the right converter. Now with the dual plane and maybe not the greatest heads and comp(not saying your heads and compression are no good.....I dont know what your heads and comp are so this is just speculation), you can whack that estimate down to say 375(or even worse with stock heads). Either way, if the heads are up to the task and the compression is pretty ballpark, youve got a pretty nice combo that Id expect it to run mid 12's or so with the dual plane intake and milder converter in your typical weight streetcar and you should have a little better than 400 horses(roughly 425-435 with good heads).

[camaroman7d]

I agree it sounds like a solid combo. If it is on a 110 LSA, (anywhere from 108-112) that's perfect for your combo (IMO).

What heads are on this engine? That will be a big determining factor of how much HP you're making.

With decent heads you should be in the 450-475HP range (at the crank).

Edit: I was posting at the same time as Greg. I agree with what he wrote. I had a similar combo and was in the 11's in a 3500lb Camaro. I did have a single plane intake and a tad more stall.

[Larry's 69]

Great info guys. Sportsman II heads, 10.1 ratio. Thanks.

[greg moreira]

Although they are worlds above your typical old school head, they still arent monsters. So with that in mind, Id say you will be definitely shy of 450. But it should still have 420 horsepower potential or a little more in there with those heads, the dual plane, and of course some dyno time and tuning.

Hey Camaroman7d, isnt it weird how that happens? From time to time I will end up posting at basically the same time as others, and it seems like every time that happens and my post is entered second, I say exactly the same thing as the previous poster to the point where it often looks like and makes me feel like I basically copied hehe(and Im sure it looks like it too so I always re-post or edit so the others know and it doesnt continue to look funny). I always thought it was pretty funny how that happens.

[camaroman7d]

Larry, That car should be plenty fun as it is. Once again I agree with what Greg posted as well.

Greg,
I am not sure when the time stamp goes on the post (when you start typing or when you hit the post button). I did feel the need to go back and edit for the same reason you mentioned (we were saying the same thing).

[greg moreira]

Yeah, didnt mention, but even though it might not have the best heads out there, and it would benefit with a single plane intake...its still a nicely built engine and it will still be real fast and real fun to drive(probably more fun to drive than if you did have a bigger port head with a single plane cause it would tend to feel a little lazier on the street). Still well into the 12's for sure. Now busting into the 11's would be a hard task as is, but still a solid 12 second car is very fun for a street strip car and Id say you are there.

I dont know how those time stamps work either. I just know that when I post at the same time as another guy and mine falls right after his, Im almost always going awww crap cause its like I read his mind to me(but it doesnt look that way...it looks like I cheated hehehe). Eh well. $h!T happens.

[Larry's 69]

Thanks for all of the input and knowledge, guys. Once I dyno and go to the strip, I'll let you know how I made out.

[thrasher]

Originally Posted by Larry's 69

Sportsman II heads, 10.1 ratio.

Did someone actually measure the deck height, combustion chambers, and figure the dome or reliefs on the postons to come up with that figure of 10:1?
If not it's likely you don't have 10:1.