need real world cam input

[95stroked1500]

i have a 383 i built for my street truck, but decided to put it in my blazer.

the cam isn't too radical, but it's not small either. i'd have to dig the numbers back up, but i think with my rockers my specs are somewhere about a 214 I/ 220 E duration with .52 lift, hyd roller cam.

other pertinent info to reflect the performance on a whole, AFR 180 cc runner heads and a holley stealth ram fuel inj., compression ratio around 9.8:1 off the top of my head, 1 5/8 headers, dual exhaust.

trans will be 4L80E, stall converter in the 2000 - 2200 rpm range.

the main use of this will be daily driving. no real serious off roading like the rubicon, etc. i will plow snow down my road in the winter with it. it will occasionally tow.

i have a similar cam in my street truck with a 350, no stall converter. i have towed some heavy loads with it. i don't have any problems. i get 20 mpg.

i'm figuring on the whole, the cam in the 383 should work. but i don't have the hands on 4x4 building experience to really know for certain. has anyone had hands on experience that shows i should swap the cam before i stab the engine?

would added low end torque from a diff cam really make a real world diff for my use?

what gas mileage diff would i realistically see with a smaller cam in for this application?

 

[b454rat]

I ran a 230 duration in my old 400 that I drove back and forth from Binghamton NY to Ottawa CA for 6-7 months. Was my driver at the time, and put 60k on it on those months. Only problem I had was now and then busting a rocker arm, the springs were stock and with the .480" lift, just about at the max for bindage.

 

[omgang]

I have a 406 in my '76 K5. It has a Comp cams 280 magnum (.480 lift; 230 deg. duration; 110 deg. lobe center) in it. I'm running Vortec (GM) heads machined for larger springs and Keith Black pistons with 5.7 inch rods. I also have a Performer RPM intake. The larger displacement (compared to a 350) tends to smooth cams out and make them less obnoxious. My Blazer idles at around 700-800 rpm and has decent low end. It definitely likes rpm though and really comes alive somewhere around 3500 rpm (throttle response becomes fantastic, tons of power, etc.).

The AFR heads you have with the 180cc ports are going to want more rpm as well. Smaller ports typically means higher velocity at lower rpm while bigger ports make great high rpm power at the sacrifice of lower rpm torque (because intake velocity is slower in the bigger port). I don't think the cam is going to be too much of a factor because the duration is very decent (less than mine).

To really make it work well in the truck you'll want correct gearing for the tires you want to run. I have 33's with 3.08 gears and the engine hardly ever gets into its sweet spot. I will manually keep it in first or second gear (auto tranny) when I want to allow the rpms to come up and really get some power to the ground.

OM Gang

 

[95stroked1500]

in designing the build for my street truck,... lower end torque wasn't a factor i needed, but i didn't completely sacrifice it all away. i spent months researching heads. there were 2 aspects on the AFR 180's that led me to choose them.... they had good low rpm velocity, but out flowed many others in the upper range.

you guys have some hefty cams.... looks like i should be in great shape. all the other builds i've seen similar to mine running cams in the ball park of what you guys have..... i'd have 500 hp with a cam like that. sure is tempting.

thanks for the input.

 

[4X4HIGH]

I'm running a Comp Cam #08-464-8 specs are...

Duration @ .050" = 202/212*
Gross valve lift with 1.6 rockers = .550"/.546"
Lobe separation angle = 113* installed @ 109*

I'm also running the AFR 180cc heads with 65cc chambers with an exact CR of 9.489:1. My engine is a 355 (350 +.030" overbore) and i'm running a 454 TBI with 98lb/hr injectors at 18psi fuel pressure and a chip from TBIchips. This engine hauls ass AND is smog legal and passed with flying colors last year. Here is a pic of what it looked like before i installed it. Should also add that this engine is 400hp @ 3500rpm and 520ft/tq @ 2000rpm and flat torque curve up to 3500 then slowly drops off.

 

[95stroked1500]

now that's impressive!

when i was first looking into my build i was talking with a guy who has a 383 similar to mine in specs, but in a burban (he was running diff heads though). he used a 454 tbi,. burned his own chip, and his was nutty.

... i've got a 454 tbi laying around and really considered using it.

but in discussing things with another guy who taught me how to burn my own chip, i ended up siding for the stealth ram. but with your results,... i think i would have been just as happy and would have that $2G to put into other areas.

.... cali tail pipe emissions is one more thing i was trying to meet in my build.

 

[4X4HIGH]

now that's impressive!

when i was first looking into my build i was talking with a guy who has a 383 similar to mine in specs, but in a burban (he was running diff heads though). he used a 454 tbi,. burned his own chip, and his was nutty.

... i've got a 454 tbi laying around and really considered using it.

but in discussing things with another guy who taught me how to burn my own chip, i ended up siding for the stealth ram. but with your results,... i think i would have been just as happy and would have that $2G to put into other areas.

.... cali tail pipe emissions is one more thing i was trying to meet in my build.

If you live in California or plan to move here they also do a visual inspection and i don't know if the stealth ram is 50 state approved. If it's not 50 state approved with a CARB EO# then it would automaticly fail an emissions test regardless of what the tailpipe says.

Here is what i did with my intake manifold so the 454 TBI would work. I had a friend set it up in a CNC mill and bore the throttle bores larger. Basically i figured out how big they needed to be (2" + a few thousandths) and he bored the holes so that they were just larger than 2" at the top but tapered down to the factory siaze at the bottom (this will build more velocity that being straight bores).

 

[95stroked1500]

yep, i already live in the people's republic of california. a few hours north from you. let's say, as long as i'm good out the pipe i'm good to go . the other option if i had to is a referee. i'm think i could get approval for the upgrade. i've already got a back up plan to tap into the manifold and run an EGR if i had to. like factory vortec engine style, where they take exhaust from the exhaust manifold (header in my case) and tube it to the intake manifold with the EGR valve inline.

i've got an edelbrock performer TBI manifold too. great minds must think alike. if i ran the TBI i was going to bore it out..... even though edelbrock says not to. there's a few other guys i've chatted with who have done what you did with good results.

.... although you've got the best results i've seen yet. most people can't get that much power, can't get the fuel delivered. looks like the fuel pressure boosted to 18 psi does the trick.

you have great results. when it comes time i think i'll probably rebuild the 350 in my street truck similar to yours. then pass it on to the kid to start driving in another year or two.

 

[79rustyk10]

I'm also running the AFR 180cc heads with 65cc chambers with an exact CR of 9.489:1. My engine is a 355 (350 +.030" overbore) and i'm running a 454 TBI with 98lb/hr injectors at 18psi fuel pressure and a chip from TBIchips. This engine hauls ass AND is smog legal and passed with flying colors last year. Here is a pic of what it looked like before i installed it. Should also add that this engine is 400hp @ 3500rpm and 520ft/tq @ 2000rpm and flat torque curve up to 3500 then slowly drops off.

I wouldnt turn a kid loose with something like that, Im 24 now and probably still not ready for 520 ft lbs at 2 grand. never the less, vey very impressive.