I defiantly don’t have the funds to build a stroker. I know these pistons screwed me from the beginning but it is what it is. Everything has been balanced and I don’t have the funds to have new pistons rebalanced once again. So I have to make with what I have. I am all game for using a thinner gasket because if it bumps me up that much I feel that it is a worthy investment for thinner gaskets. I thought this came was pretty good even though it came in a rebuild kit. So in summary I will be investing in the thinner gasket also will be milling the heads. Would this be sufficient? It seems you are running 48cc in those chambers. If I can should I mill the heads down even farther for compression? I wonder if piston to valve clearence would be an issue if I milled even farther. These pistons defiantly didn’t help but I have to deal with it. 300 to the wheel should be sweet and I will do my best to make up power in other areas and make the best of it. I talked to comp came and they mentioned a cam very similar to mine. I cannot replace the pistons it is to late because of balancing so I just make it up in other areas. Maybe in a later build when money is more eveilible. Beginner mistake So I will do everything to make up the compression but besides that maybe a underdriven pulley system, carb spacer, perfect carb intake system etc. seems to be my option. I feel 10:1 Ian my best bet for compression and the I will try to combo with a 1.7 roller rocker as well as take away strain from the motor with the accessories
His comp ratio is in the 9's. Nothing wrong with that. And Ford's rod specs are 5.095, nothing going to change that. If he wants to wake it up with that ratio, then run an EFI grind cam with a wide LSA. Someone's put it into his head that his comp ratio is screwed. Nothing could be further from the truth. But y'all keep fucking with him by putting it into his head that anything less than a 10 to 1 comp ratio is worthless.
Build your motor as is with those pistons, there's nothing wrong with them. Mill the heads .040 and call it good. If you want to bump the dynamic comp ratio, then run an efi cam with a wide LSA. It'll run fine, better than you think.
The cam you picked is similar to a B303 with 1.7 rockers. I've run a B cam and 1.7's with a 9 to 1 comp ratio in a roller 5.0 and it was a screamer. Don't let these naysayers tell you your build will be less than optimal. Put it together and run it before buying anything else. Mill those heads .040 and run a Felpro 9333 gasket. Use 1.6 ratio rockers but check the piston to valve clearance before bolting those heads on permanently to be sure the 2.02's will clear the valve reliefs in those pistons.
I kinda figured all that but was only painting a picture of where you're at and what extra effort will be needed to maximize the final config. Then you can apply lessons learned to your next powerplant later on down the road. You asked specific questions about how to maximize these little short stroke motors and I gave specific answers to help YOU make more informed and educated decisions. I'm a very progressive engine builder who generally chooses to maximize anything and everything possible while an engine's apart and parts are being gathered. BUT.. I generally do NOT impose my own personal standards on others as they will have to acquire their own knowledge base over time to fit within their specific budgets and builder skill level. If asked and I can find time I'll give the pro's and con's of a build decision and you'll inevitably decide how you'll spend YOUR time and cash any way you see fit. Unlike some people who impose their own standards because they're seemingly happy enough with what they have, I'm not stuck in the 80's and 90's being content with wide LSA EFI style cams because plain and simple.. they give up average power. Comp cams would have likely rec'd one of their cookie cutter cams ground on a 110 or even 112 lobe separation angle. That's just what they do over the phone. Call 3 times and you'll likely end up with 3 different grind numbers, sometimes multiple choices from the same phone tech depending on his mood that particular day. lol Then call a custom cam grinder and I bet they give you max 110 or even a 108 LSA grind spec intended for carb'd applications rather than an EFI grind that is designed to idle better to keep the engine computer happy and ultimately gives up peak torque in the process. Most grinds these days are designed around 4 degree advance positions and at the very least, I'd be going 2-4 degrees further on the spec'd installed centerline(ICL) to pump up the lower portion of the torque curve. You're basically implanting the heart of the motor and if you want a cam that adds power then look at Comp's Extreme Energy series or Lunati's Voodoo line. Those lobe designs will be miles ahead of any alphabet cam from yesteryear. Better grind spec and more compression could be an easy 10-12 horsepower and 15 ft/lb AVERAGE gains, even higher peak gains.. which is a lot for a smaller CID motor like this. And I'll say it one last time before I'm done with this typical roundy round bs. Those big bore gaskets are a just a flat out poorly advised choice when there are so many other options that will boost and restore some compression that was lost with those 8cc symmetrical relief pistons. Why anyone would specifically choose to use a 4.100" big-bore gasket on a 4.020" bore motor intended for street duty is beyond me. Usually happens when they have no knowledge or understanding of the little details that affect combustion space efficiency and its affect on burn characteristics. Which ultimately affects the final tuning resolution and available latitude needed to get there. You asked about compression and how to maximize this little motors powerband and I've tried to convey what I currently know and understand from a lifetime of trial and error and focused study. PS. if you REALLY want to know how this motor will run and tolerate pump gas?.. input your cam spec's into a calculator to find out where the DYNAMIC compression ratio(DCR otherwise known as "running compression") will end up. DCR's valve open positions relative to piston location(and speed/engine rpm) is what your right foot/brain determines to be good enough.. or not. As it sits now you'll likely be into the high 7's for DCR which does not a highly responsive torque monster make. PM me if you want more DCR input(through my engine building program) or have more specific questions. PSPS. forgot one last little tidbit of info.. not because I want to debate or argue.. but because I'm willing to share. Most 2 valve wedge style cylinder heads(GM Ford and Chrysler non-hemi) are going to lose about .6-.7cc's of combustion space per .010" milled. Probably also listed on the mfgrs website and/or the installation manual for that particular part #. With that said, I'd cut .050" to move closer to your goals. Take care and good luck with it all, Greg
Wide LSA EFI cams don't give up anything. That's hogwash. I've run them. My 331 has the Z303 in it. (LSA 112*) Powerband is 1500 to 6500. I've run the B303 (LSA 112*) with the same heads that are on my 331 now but on a 40 over 302 with reman flat tops, likely the ones that had the 1.585 pin height and the lift augmented with 1.7 rockers. Intake was a Vic Jr topped with a 650 DP Holley. Powerband ? 3 grand to 7500. I've also run the stock F4TE Ford cam (LSA 116)found in 94-97 5.0 and 5.8's in a 5.0 with home ported E7's topped with a Ford A321 intake (same as the old Shelby Cobra dual plane) and three different carbs. Powerband ? idle to 6000. If anything a narrow LSA will only show gains at the very top of the rpm band, a place that's rarely ever seen on the street. The EFI cams give you a broader torque curve which is exactly what's needed on the street.
Clearly misunderstandings of how cam timing and ICL/LSA work to affect cylinder pressures. Use it correctly and it's just another fine tuning tool to plump up one end or the other of a powerband, is all. It's a refinement and maximization process. Here's a good sense of what goes on as the valve events(specifically IC) get moved around. Not like a supercharger or nitrous tpye night and day difference but the effect is quite pronounced on an engines powerband and overall throttle feel, especially as rpm climbs and more power strokes occur within a shorter period of time. OP's current parts config cranking and DCR(1.7 intake rockers cam installed "straight up") wider LSA "EFI cam" with later intake opening cranking and DCR(installed "straight up") Theoretical tight LSA 4 degrees advanced parts config cranking and DCR Recommended parts config @2 degrees advanced cranking and DCR And one last version for fun, which is part of the whole point to learning and doing all this kinda stuff, with a rowdier cam LSA/ICL. Not saying you should go there.. just showing the trends to help anyone who's interested learn something they can apply to their own stuff. Note that this is when you start really getting tighter PTV clearance issues cropping up and why most racier 2 valve relief pistons have deeper valve notches for bigger cams and high compression. Luckily the silver lining with your 8cc pistons having some decent notch depths will allow you to push the PTV envelope harder when it comes to head milling lift increases and advanced cam timing. And here's your specific cam spec's. Didn't search before and not as bad as I thought(112/114 LSA).. at least has a little tighter 110 LSA to help build more cylinder pressure sooner and faster. If you have a 9 keyway crank gear then start at 2 degrees advanced and degree it there to determine exact ICL. Also would point out that 231 degrees @.050" is still a decent sized stick for a little 304" short stroke motor which is why the mfgr is recommending a minimum 10.25:1 static compression. Killing off or just plain disregarding the effects associated with nearly a full point of compression will really soften this motors power peaks, especially first 3,000 rpm of rev range. In the end, adding compression is one of the only sure fire ways to fix too big a cam in a little short stroke motor and it pumps up the volume everywhere from idle to past redline. To your right foot and brain the motor will feel bigger than it actually is.
Apologies to anyone that took the time to read and study.. rattled on too much as usual and didn't catch my errors on the reread. Should have conveyed that it's Intake Valve Closing(IVC.. not IVO)) that has the major impact on cranking/dynamic cylinder pressures. Useful swept cylinder volume measurements can't begin until the intake valve is closed on the compression stroke. Anything much over 9:1 DCR will begin to feel like a stout motor from idle to redline with the right supporting parts. In current 58cc regular gasket config my power guesstimate is around 315-320 @flywheel. With near 10:1 static 54cc thin gasket and preferably 2 degrees advanced ICL, I'd lean much closer towards 340+ @flywheel with MUCH more power and throttle response below 2,500 rpm. Another few pro-compression tidbits. More compression will help wake up the moderate sized cam and snaps the intake charge into action sooner during the intake stroke which really improves a carb boosters response/performance, especially at lower rpm's. Adding compression also contributes towards higher induction pulse strength via quicker rising cylinder demands which works to resist intake reversion and, assuming no major flow restrictions, also improves exhaust system scavenging as exhaust pulse strength and purging pressure/speed increases. An open header on the track would see even larger gains from added compression. Mainly because most shelf header 3" collectors are sized too big for near all but the rowdiest high compression little 302's that power peak past 7,500 rpm. But don't even get me started on exhaust theory and design or this post and the next will look like the last few.
Wow you defiantly know your stuff! Full of knowledge and is much appreciated. I do plan on going about the heads and gasket as you stated mill them down to around 10:1. To conserve the loss of power I am going to be using electric fuel pump and to also aid I am going to hook up electric fans. For the carb I am looking at a 650 double pump mechanical secondary https://www.summitracing.com/parts/hly-0-82651sa/ Something like that how is that to be paired up with the weiand stealth intake. I also have some heads with the 3” collectors I believe at the end.
LOL.. stock block spec's with bigger cam(despite cam mfgrs compression rec's right there in black and white)?. It's like polishing a turd with.. well.. a turd buffer. Seems like some fall back on their own personal yardsticks when they don't understand the science behind a specific combination of parts. Happens often which makes it kinda tough to add to an always full glass. Math, science, and physics is what all this parts combination stuff boils down to. Billions of dollars in R&D has already been spent by OEM's, racers, and hotrodders to find the trends and develop parts around them. At this point it's hard to totally reinvent the wheel and the most diligent copy-cats get rewarded with the best running engines. BTW, stock 5.0's were horrid for any topend power.. well any real power at all till you dumped thousands in induction(especially heads), exhaust, and rear gear.. to basically end up where the OP wants to end up here. Many called them "tractor motors" because they fell over a pretty steep cliff right at 5,000 rpm. They were fun cars/motors for the day but let's get real here. Installing a bigger cam topped with better heads on 9:1 shortblock sure won't match the stock cams tire chirping torque curve below about 2,800 rpm, the motor will struggle to build rpm and accelerate in taller gears( and a double pumper will only make matters worse here) till it comes up on the cam and carb boosters and layover quicker on the topend and especially past peak HP. Compression is not a bad thing for this motor and will make the right pedal feel better all around. Just relaying what most seasoned motorheads already know and understand to be non-debatable science. Here's one of, if not THE best ICE overviews I have ever come across pertaining to an older cup motor. It's very long but well broken down into properly delineated subgroups. Enjoy.
We're not talking about a stock 5.0 here. He's got heads to put on it. The stock heads were the bottleneck at 5 grand. Once again, you're trying to baffle with bullshit here. Those heads are fine with a 9 to 1 range comp ratio but with a different cam. No need to push the limits in milling then running thin gaskets to compensate to get a 10+ to 1 comp ratio. And then trying to get the intake to fit afterwards. Not everyone wants or needs an all out race motor, especially on the street. He may think that's what he wants, but he'll be extremely disappointed with the final outcome once he drives it. It'll end up being a high strung tempermental beast that's hard to tune. But then hey, it's his money. I'm going to shut up now, you go right on giving advice to him. I know who he'll blame when it turns out how I think it will. He's a first timer here building a motor, I'll let him learn the hard way.
LOL. when you start building 10 second motors and begin to convey that you actually understand the physics and geometry involved with all this stuff then I'll be all ears. Until then it appears you're just a bolt-on guy with some different standards than others. Also maybe little stuck in the past?.. adamantly announcing alphabet cams as something even remotely close to state of the art by today's standards. Yeah, everyone starts somewhere.. but why start building a motor to 80's technology standards? There are better ways to do things and building compression is being directly advised by the cam mfgr. But what the hell do those guys know about anything, eh?
He's a kid. He doesn't need a 10 second motor in a street car. Maybe you're a little stuck on yourself. I fully understand all this. Been there done that. And funny you should mention state of the art in camshafts today. I've looked at the specs and looks to me like the same old shit from 20 years ago is out there. There's only so much you can do with a pushrod cam. The new tech today is in the newr engine designs and the real change there is variable cam timing.
