351 cam help

zm830101 · Dec 8, 2005

anybody using this cam in their 351
comp cams xr-288rf hydraulic roller
int@ .050 = 236
exh@ .050 = 240
advertised duration is 288/294
.555/.576 lift
110 lobe seperation.

it would be matched with a .030 over 351, 9.5:1 comp
edelbrock victor jr heads
rpm air gap intake
750 cfm holley

what do you guys think? would this make for a healthy combo in a weekend warrior?
:SNSign:

69Rcode_Mach1 · Dec 9, 2005

Change that intake manifold to a Vic Jr. and then yes. I used to have an RPM Airgap.

Jc69Stang · Dec 9, 2005

69Rcode_Mach1 said:
Change that intake manifold to a Vic Jr. and then yes. I used to have an RPM Airgap.

Yup, good cam, upgrade the manifold and you should be set.

D.Hearne · Dec 9, 2005

I'd leave the manifold as is. I'm running a Ford Racing Z303 in my 331 stroker ( .585 lift w/1.7 rockers, duration is 228 @ .050, 290 advertised-- 112 degree lobe separation if I'm not mistaken) With the high rise dual plane 3x2 intake and three Holley 250 carbs, power comes in at 1500 and pulls like a freight train to 6500. A single plane will only move the power band upward, there by moving the top rpms into an area where you're just stressing the bottom end.

rbohm · Dec 9, 2005

before you decide on the intake, and the air gap and victor jr are good choices for this combination, i would first decide if you are going to run this on the street on a regular basis or not. if you plan more street duty than race duty, then the air gap intake is better, otherwise get the victor jr

zm830101 · Dec 9, 2005

i'm keeping the air gap. like i said, it will be a weekend warrior so it will see primarily street duty. would the XE 282 for a 302 have a better idle and perform similarly in this combo?

zm830101 · Dec 9, 2005

what is the retrofit all about?

comp lists the part number that i posted first (comp cams xr-288rf hydraulic roller) as a retrofit kit.
is this a standard base circle cam or is it smaller to work with the lifters? or are they simply calling it a retrofit because the lifters are not stock replacements? anybody know?

86bluecobra · Dec 10, 2005

I quickly through your numbers in desk top dyno. with a dual plane intake the program say that engine will make 439 hp @6000rpm and 423 ft/lbs @ 4500 with the XR288 cam. same came and a single plane makes 489 hp @ 6500 and 443 ft/lbs @ 4500. @ 6000rpm it makes 475hp and at 4500 it makes 437 ft/lbs the dual plane does make more hp and torque then the single plane to 4000rpm. which on the street you usally dont go over just cruising. i have a dual plane on my 351w but i will shortly be trading it for a single plane. when i race at the track the lose down low is easyly made up for with my nos. i should also think agout robbing a 302 block i have sitting and getting a roller cam stick.

86bluecobra · Dec 10, 2005

i beleve retro fit is for blocks that didnt have holes drilled in valley. they don't have the mounting holes for the fingered hold down.

D.Hearne · Dec 10, 2005

86bluecobra said:
I quickly through your numbers in desk top dyno. with a dual plane intake the program say that engine will make 439 hp @6000rpm and 423 ft/lbs @ 4500 with the XR288 cam. same came and a single plane makes 489 hp @ 6500 and 443 ft/lbs @ 4500. @ 6000rpm it makes 475hp and at 4500 it makes 437 ft/lbs the dual plane does make more hp and torque then the single plane to 4000rpm. which on the street you usally dont go over just cruising. i have a dual plane on my 351w but i will shortly be trading it for a single plane. when i race at the track the lose down low is easyly made up for with my nos. i should also think agout robbing a 302 block i have sitting and getting a roller cam stick.

Y'all keep posting all those "theoretical" power numbers from a computer, but that doesn't tell you how it will act in real life on the street. What it makes at 4500 and 6000 rpms doesn't tell you squat about how it acts from idle to there, which is what you need on the street. With a big cam and a single plane intake, ( and to some extent with a dual plane) there's a flat spot off idle till you enter the power band. The lower ( or sooner) the power band comes in, the better it is on the street.

brianj5600 · Dec 10, 2005

My dyno sim says 350tq at 2000rpm's and 400tq by 3000rpm's. Bumping compression to 10.5 helps too. That cam in a 351 is not "big" IMO.

D.Hearne · Dec 10, 2005

brianj5600 said:
My dyno sim says 350tq at 2000rpm's and 400tq by 3000rpm's. Bumping compression to 10.5 helps too. That cam in a 351 is not "big" IMO.

In relation to a stock type cam it is The Z303 in my 331 is a big cam according to Ford. But with the combination I have it in, it's perfect IMO.

ddonaca351 · Dec 10, 2005

Well my Lunati 51017 is 218/228 @50 and .536/.536 on 112 sep. It idles with a niiiiccee lope at 900, pulls 13-14" of vac at idle, starts pulling pretty good about 2500-2800 (its a "351" cam in a 302) and starts pulling reeeeaalll good about 3500. It makes a hair over 300 at the wheels (again in a 302) and thats with the computer. A carb'd motor would probably pick up another 10-15 horses with a dual plane, and still have great torque.

Oh, ( IMHO ) you can simulate all you want, but in the real world... a single plane almost never, ever runs well down low. (unless its on lottttsss of inches.... like a 393/408 perhaps)

Dave-

KillerKittyCat · Dec 10, 2005

D.Hearne said:
Y'all keep posting all those "theoretical" power numbers from a computer, but that doesn't tell you how it will act in real life on the street. What it makes at 4500 and 6000 rpms doesn't tell you squat about how it acts from idle to there, which is what you need on the street. With a big cam and a single plane intake, ( and to some extent with a dual plane) there's a flat spot off idle till you enter the power band. The lower ( or sooner) the power band comes in, the better it is on the street.

I agree!!!! I have a 69 kitty vert parked in the garage. 351W with 10.5 to 1, hydraulic roller, 950 Holley, 2 1/2 inch exhaust and a single plane manifold. It dyno'd at 456. It gets 6 mpg. That is why it is in the garage. 0 - 30 sucks. I get to 35 and drop it back to first..... I am gone!!!!! I destroyed five trannys before I finally made it an auto stick. It sounds nice but is not a daily street driver.
I had it built (my first hot-rod). It will pull 7000 rpm easy. I had it at Sears Point for a run (just for fun) and they shut it down at 150. Still had rpm to burn.

(Dad it's a nice day, can we take the convertible out. Sure son, let's park it in the driveway, put the top down and I will get the circular fan out and put it on the hood!!)

zm830101 · Dec 10, 2005

86bluecobra said:
I quickly through your numbers in desk top dyno. with a dual plane intake the program say that engine will make 439 hp @6000rpm and 423 ft/lbs @ 4500 with the XR288 cam. same came and a single plane makes 489 hp @ 6500 and 443 ft/lbs @ 4500. @ 6000rpm it makes 475hp and at 4500 it makes 437 ft/lbs the dual plane does make more hp and torque then the single plane to 4000rpm. which on the street you usally dont go over just cruising.

thanks 86bluecobra for this info. i really can't wait to get this thing together. :SNSign:

zm830101 · Dec 10, 2005

KillerKittyCat said:
I agree!!!! I have a 69 kitty vert parked in the garage. 351W with 10.5 to 1, hydraulic roller, 950 Holley, 2 1/2 inch exhaust and a single plane manifold. It dyno'd at 456. It gets 6 mpg. That is why it is in the garage. 0 - 30 sucks. I get to 35 and drop it back to first..... I am gone!!!!! I destroyed five trannys before I finally made it an auto stick. It sounds nice but is not a daily street driver.
I had it built (my first hot-rod). It will pull 7000 rpm easy. I had it at Sears Point for a run (just for fun) and they shut it down at 150. Still had rpm to burn.

(Dad it's a nice day, can we take the convertible out. Sure son, let's park it in the driveway, put the top down and I will get the circular fan out and put it on the hood!!)

sounds like your 0-30 and mileage trouble is in the carb...that is A WHOLE LOT of carb for a 351. i say find a 750 and see what happens.

after just quickly doing the math, even spinning it to 7000 with a 90% VE you would still only need 710 cfm.

D.Hearne · Dec 11, 2005

zm830101 said:
sounds like your 0-30 and mileage trouble is in the carb...that is A WHOLE LOT of carb for a 351. i say find a 750 and see what happens.

after just quickly doing the math, even spinning it to 7000 with a 90% VE you would still only need 710 cfm.

I agree, swap out the single plane for something like an RPM air gap or an older C9OX Ford intake, top it with a 700-750 and it'll behave on the street and still pull to 7000 rpms.. Two years back when I overhauled the 390 in my 68 Merc, I topped the 428PI intake with a Holley 850 DP, simply because it was on hand and the only thing big enough for it. It ran great once you got going, but nail the gas from a dead stop and it would fall flat on it's face. Tried a 600 VS Holley and it pulled so much vacuum at idle, it was pulling the secondaries open, making it hard to keep the idle set. It's now got a 750 VS Holley which is perfect for it.

69Rcode_Mach1 · Dec 11, 2005

And here is a third opinion as well. You are way overcarbed. People don't even run that much carb on strokers. That is a big block sized carb you are running which is why it doesn't pull anything down low. If you want it for the street go with vacuum secondaries you will want to especially cause you are an auto. You are having these issues because it is an auto and overcarbed. My 5 speed helps tame some of these issues, and gearing will help also, but if I had an auto I would be a lot more limited to my options for the street.

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