What started out as a cam, head and rust repair, take the week off from work to do it, has turned into the berthing of a 331 ..... I just couldn't see myself putting in a new cam, AFR heads and new headers when my motor is out the car and all tore down..... Now for a little "better pre-planning" while my box from Summit is on the slow boat to Hawaii...... Dropped the block and heads off at the machine shop today for a check up and HOT Tank so here is what i will be working with when it gets back. 71, 302 block- rebuilt once bored 30 over AFR 1422 heads 650 Holley (if i can get it to act right Headmen headers 88300 SCAT Kit from Summit https://www.summitracing.com/parts/SCA-1-94055 New 28 oz balance will get the new crank balanced once it gets here....... Am i missing anything?? oh yeah.... 262/270 COMP Cam kit and all the fixings.... https://www.summitracing.com/parts/cca-k31-238-3 What should i start looking at setting my timing at? Should I start thinking about a cam upgrade already? Now that I am knee deep into it i see that i am in over my head, all you Maverick/ SBF Pros out there have always given me GREAT info in the past so PLEASE FEEL FREE to send me your comments forgot to mention the 1.6 scorpion roller rocker........ so please let me hear from you experts out there.......
The cam is a good choice for a "high performance" application. It would be similar to a Edelbrock Performer RPM. It would want a higher compression ratio than stock. What compression ratio will it calculate out to with the AFR heads? I would order up the Comp Cams break-in oil to make sure you don't wreck the flat tappet cam. MD
Yea, you're going to want more cam. That's basically and "RV" grind. With my 331 I went with a Ford Racing Z303 roller with 1.7 rockers to work the valves in my Canfield heads (same as AFR 165's) My intake is a high rise dual plane repop Ford 3x2 with three 250 cfm Holleys. My comp ratio is 10.4 to 1. Power comes on at 1500 rpms and pulls to around 6500. Excellent street manners, great mileage too. This cam specs at .587 lift (1.7 rockers) with a 228* duration @ .050 lift and a 112 LSA. Motor has boat loads of torque and HP.
I disagree on the RV cam comment. A RV cam would be down at 210 or 212 degrees duration at 0.050 lift. The cam listed by the poster is 218 * intake and 224 * exhaust at .050 lift. Having said that, if he can get the compression to 10.4 with the stroker kit he ordered, then the Z303 might be a better choice. " Excellent street manners and great gas mileage " are in the eyes of the beholder. MD
Yea, but he's picked a flat tappet grind (in deference to his block) which has slower ramp rate compared to a roller ergo, it's more like an RV grind, both in lift and duration "under the curve" It might be an OK cam for a 302, but the extra cubes are going to tone it down, just as they did with the Z cam. When I talk about street manners and mileage, I'm talking about a cam that's easy to live with in idle quality (doesn't need a lot of fuel to get it to idle, so you're not smelling gas fumes constantly) and driveability, no stalling and stumbling when you go give it the gas. Sounds to me like you've never tried an EFI grind with a carb, if you had, you'd know what I'm talking about. It's not something I imagined, it's what I've experienced. There's no reason you can't use a bigger cam with a lower comp ratio, with an EFI grind, you can have your cake and eat it too (made possible by their wider LSA's) . And he hasn't mentioned the intake he's going with, that too has a big effect on where the power's going to be made.
Thanks fellows for your input, all this friendly discussion has me thinking. I know that i put the cart before horse with i brought the cam kit first, but the 331 was an after thought. My intent was just to add the cam and AFR heads...... but then i got a bright idea and the promise of a new job with better pay and figured what the HELL, might as well do it now cause in 8-10 months i would want to pull it out and stroke it anyway... (no pun intended)....... - I will be running an Edlebrock performer intake, I have an Eldebrock 4brl and a Holley 4brl... I want to go with the Holley cause its less than 6 months old, but my edlebrock carb has proven to be pretty plug and play.... with less... stopped by to drop off the crank to have i balanced today, got to take the flywheel and damper tomorrow so hopefully my machine guy will be able to tell me what compression ratio i will be looking at, once he does the numbers. Will keep you posted...... any other suggestions, feed back or input?? An I owe a picture under a palm tree.... Will get that out there as soon as i can....
Hey everybody on the forum, Jay is building a 331 stroker and is willing to hear our advice. Don't let this thread head to the archives! Let's hear it! MD
Not sure why you think a Holley is somehow troublesome ? If you don't tune a carb to the engine it's sittin on, you'll never get the full benefits of it, no matter who's design it is. Once you tune a Holley, it'll stay that way for years. Anyone who tells you otherwise is full of it. You also didn't specify what Holley it is, nor the Edelbrock carb for that matter. The Performer intake will choke a 331. Not much point in building a 331 if that's what you're gonna put on it. Bad Choice.
Hey Jay, I think the best thing is to decide what type of engine you want and how hard you want to run it. High horsepower requires high RPM. Obviously from the stroker kit you're going to get more torque and resulting HP at every RPM, but to really get a high HP number you need to be able to rev in the 6000 RPM range. Since you mentioned Edelbrock, take a look at the Performer series vs the Performer RPM series, both with intake manifolds and cams. The Performer series is for a mild mannered engine. The Performer RPM series is is to extract more power out of the engine and give a higher horsepower number by allowing the engine to still produce torque at a higher RPM. MD
These guys give great advice so far and the last post by MD nailed it too. If you can clarify what trans/gear/tire size and overall intentions with the motor is would be faster and simpler to give much more accurate parts and tuning info. Do you like short rear gear and lots of rev's to drive it like you stole it?.. prefer lower rpm torque for cruising around more than revving and racing like a teenager? Maybe a bit of both? Are you a bit of a high speed highway racer? Planning any drag strip duties? etc.. etc. Main point is this. Without having EFI and variable cam timing, you generally always want to cam an engine around the intended usage model(average power range requirements). The gears and final drive ratio(existing AND/OR near future changes) have a huge affect on the final results for any combo and need to be very heavily considered. In a nutshell.. the meat of the engines/cams power production needs to be moved around to match everything else. Kinda stabbing into the dark here but based on those cylinder heads, my quick cam picks are the Lunati voodoo and comp's extreme energy lineup. The newer Lunati bootlegger is another even more aggressive if you suddenly decide you want to be one of those 1%'ers. And either one of those would be about 2 notches more aggressive than the one you posted. The AFR heads are not overly strong on exhaust flow without further work either, so if you want some extra rev potential be sure to add more duration split on the exhaust side(bootlegger grind linked below has more exhaust duration to keep it from nosing over so hard past peak horsepower. Howard's cams also has some EXTREMELY aggressive lobe designs with up near roller cam lift ranges these days too. Just be careful as the existing springs on those heads may not keep up with such high valve accell/decel rates and you'd need an upgrade. Another friendly FYI.. the more aggressive you get with cam timing and lobe intensity(faster lifter/valve-train movement).. increases engine rpm range and taxes the hydro lifters metering(which, irregardless of advertising, is still THE major limitation with hydro flats rpm capability). IMO, you would be much better off to build your own cam/timing kit with a short travel lifter design. More expensive but better performance and durability in the long run. Or say screw all that and move towards a solid flat tappet to avoid limitations. Well adjusted and maintained solids can hold lash for a good long time, especially on limited use seasonal toys like these. http://www.lunatipower.com/Product.aspx?id=8697 PS. dont let you're machinist get lazy! Tell him you want no more than .040" piston to head clearance. If he did get lazy then move to a thinner head gasket to close up the clearance. Despite the higher compression ratio it actually helps reduce/resist detonation tendencies. Should put static right near 10.5/1. Good healthy ratio for any street motor that can still be moderately tuned for regular.. or super-tuned for premium. The difference is easily 5-10 peak ft/lbs and greater average power.. especially below peak torque where a street motor spends most of its run time. PS.. holy crap!.. those pistons show an 11cc dish! Horrible choice for this smaller cid motor. You won't even break 10/1 static unless you nip the heads to lose a few more cc's.
Contrary to what you've posted here the RPM intakes just work as well in the lower rpms as the Performer. The difference here is the RPM lets the engine breathe in the upper rpms. You can have your cake and eat it too. That said the suggested rpm range on the RPM was based on a 289-302 cubic inch motor, bolting the RPM on a 331 with better than stock heads will lower that rpm range, just as what happens with a cam rated in rpms for a 289/302 when put inside a 331.
Those pistons in that SCAT kit aren't dished. They have four valve reliefs with a volume of 11ccs. The pin height also isn't mentioned, which is the most important factor to determine the comp ratio. He also hasn't mentioned the head's chamber volume. Both need to be listed to figure the static ratio. The pistons in my 331 have two reliefs and while I don't recall the pin height, the comp ratio worked out to be 10.4 to 1 with 57 cc chambered heads. With the Z cam and its wide LSA (112*) it will not run on anything less than 91 octane fuel with 12* initial timing. 87 octane regular ? Forgetaboutit !! That happened only once when I first fired it up. Sounded like it was crushing gravel. It's been fed a mix of 91 and 93 ever since.
