Hopefully the OP doesn't mind the slight hi-jack here, but what are "swirled intake ports"? Is that port work done to end up similar to a twisted port style entry like a GM Vortec head uses? As in.. a canted port angle to help promote swirl? Or maybe the roof was angle ported and biased to one side to end up with similar result? As another aside, sorry OP aussie mav brought the engine builder side out even though we're supposed to be talking gears here, I HIGHLY HIGHLY recommend using the LS valvetrain conversion on the SBF whenever new parts are being spec'd anyways(which is a very smart move on any budget head as those parts are where major corners get cut to keep prices down). This is easily accomplished using K-Lines 8mm liners(part #kl1997sta-w) or other comparable sleeve but I prefer the interrupted spiral liners k-line offers to allow tighter stem clearance and improve oil control. The 8mm valves are much lighter and also allow lighter springs to reduce harmonics and ultimately frees up power without loss in valve control. Many of the higher end heads are using them now too(AFR, Trick Flow, etc) and there are many "8mm conversion kits" being offered as well. Then add the beehive springs and their itty bitty retainers into that mix and things get really light and interesting.
Just to give you an idea were to be! In my car with 28.5 tire 5.14 gear I run 112.25 -at 12.00 turning 6800 RPM over the line! A 3.73 gear is way to tall for a good quarter mile gear and 28 inch tires!
I did the math on my car,&with a 4.56 gear & 31in tall tires,6700 is 135mph which is where I want to go.I would think any gear between 3.73 & 4.00 you could not get away w/ a tire bigger than 26in.
But you of all people should know that a tourqier motor can push a taller gear. 363 cubic inches trying to breath through an 8.2" deck height air-gap style dual plane manifold with a mid-range hydro roller doesn't make this combo a "7k rpm through the traps" kind of motor. Those AFR heads are decent for a 331-347 cid setup but they're not as magical on a high rpm big bored 363 setup. Mother nature makes the rules, I'm just pointing them out, is all. 5.xx gears are for high revving shorter stroke motors with single plane manifolds and big stalls. Many guys also use them in the 1/8 mile stuff. Make the motor more willing to turn the gear.. but don't make the gear turn an unwilling motor that far past its peak. Stuff wears out much quicker and breaks far more often that way.
I agree w/ groberts101. A 5.XXX series gearing w/o OD is 1/8 mile stuff for the most part. And, for very short street, non-highway usage. Noise, heat, stress and wear w/ above mention setup unacceptable for most all street use --IMO.
Any body that builds a car for use on the drag strip will gear the car to peek horsepower at the RPM they cross the finish line! I f the car is using a 30 inch tall tire a 3.73 gear will make the car a real stone on the track , it may be just right on the high way but will be a dog at the drags! unless you have 1000 hp so you can top out at 150 mile per hour a 30 inch tire and 3.73 gear don't work!
Yeah Rob,that is very true,yrs ago it was quite common to see 289s & 302s using 5.14s & 5.43 ratios to get them down the trk.You had to turn the crap out of them,8000 & 9000 rpm,because they had no torque.I`m getting ready to buy the parts for my eng. which is going to be a 410w.A light scat forged crank at 54lbs,k1 rods at 507 grams,mahle pistons w/ tool steel wrist pins at 520 grams.Howards solid lift cam(don`t want a roller right now)254 in & 260 ex duration @ .050,right at .600 lift.I`m going to adv it 2 degrees so it`s range is 3400 to 7200 rpm,not going to turn over 7 grand.I know the Roush 200s I have aren`t great but the Ferrea 2.050 & 1.600 valves I have,hds pocket ported & guides cut down,runners port matched to intk,victor jr,& a holley 850 dbbl pump.The rods are 6.250 long giving me a 1.56 rod to stroke ratio & a very light piston.The blk. is line bored w/ studs & a girdle(74 model),oil restrictors 2 through 5 mains keeping more oil on the bottom.With this short blk,later on I can go to some better alum. hds. & put a roller in it & take out the oil restrictors,but I wanted to spend the most money on the bottom end now so I don`t have to worry as much about blowing up.In a 2800lb car including me,this mtr should have the torque to pull those gears & tires to the line close to that speed,whadda think?
lol.. I think you'll need a fatter tire for all that. What'ya figure it'll make?.. maybe around 530-540 horse? There's an old saying. Power is made above the head gaskets and durability is maintained below them. You spent the money on the foundation and now it'll be much easier to upgrade future boltons with the engine left in the car. Then turn up the wick later on by bolting on a killer topend to really pull it all together. Bigger 22x - 23x cc heads, bigger solid roller, bigger intake, maybe bigger 950 carby.. even small dominator.. and you have an easy and decently reliable 600+ horsepower. I've been scouring the net trying to find some ultra-lightweight rods for my little 8.2" deck mule motor and can only get them down to around the low 500 gram neighborhood for a 5.090 - 5.155 rod length. Plus I will profile and polish anything and everything I can reach with a belt-sander and my angle grinder just to take another 20 grams off to help sneak in under 500 grams final weights. And those are already considered to be the lightweight versions in the I-beam designs so everything else short of $1,000+ rods are even heavier. Looked at plenty of K1 rods too. Where did you get that weight number for a 6.250" length rod? Sounds fairly optimistic to me unless this is a Honda sized journal? But even then, I'd guess closer to 550 grams at the lightest offering from any I beam most of us could typically afford to run. EDIT: maybe you meant these Molnar rods? http://www.campbellenterprises.com/...351W-Rods-FH6200NLB-L8-A-Molnar-Rods_7999.prt Small friendly word of advice if these awesomely light weight rods. Ultra lightweight rods can and will leave you kinda nervous later on when you really start to hit the converter higher and harder. They typically have more limited applications where sanctioning bodies have some type of stringent rpm, or power based limitations like 2bbl, cam/lifter vacuum rules, and various other restricter motor style classes. They have been whittled away on and were never designed for big power AND rpm under heavier rod angles that combo will surely see. Similar to the main message we've all been touting here.. pick you balance of power potential, longevity, and safety margin.. then take your losses on either end of the deal and get on with it all. The ultra-light piston and pins help you gain back a notable amount of safety margin though I probably still wouldn't recommend shooting for 650 horsepower at 7,200 rpm. I absolutely love light bob-weighted engines simply because they sound so snotty and instantaneously jump right to attention when you want them too. Not always about max peak power as it is the first one to hit the higher power levels first and most consistently down the track that gains a distinct advantage over an even higher powered engine. PSPS. Use a 2" spacer to pump up that jr's plenum volume. I would also consider some rather major plenum and port divider work to really make her sing. You'll need all you can get there from that little manifold. And use a 1.7 rocker on the intake side if you don't already run the higher ratio. And as long as the current springs can handle the more aggressive opening rates, maybe even move to a 1.72 or 1.75 ratio if you still need to purchase new rollers. I have Crowers 1.8's on order for my little custom solid lifter cam. Only $196 bucks for the 8 intake side. helluva deal
That's the main issue though. The OP didn't really state what balance he's after here. He didn't specifically state it'll be "strip only" and street/ strip is ALWAYS a major compromise ending up somewhere in the middle and proper balance is key. Especially when there is no OD trans in the picture. If it's all out drag duty?.. sure.. look at rpm across the stripe. But even then, the gear and stall should be chosen based on the engine combo's power peaks, torque AND hp, to keep the engine running in the meat of its powerband. What you're suggesting here doesn't fit his specific engine combo. AT ALL. It really does absolutely no good at all to put 4.30 gears on a stock engine for that very same reason. The heads and cam in particular will fall off that proverbial cliff and the motor will just needlessly spin faster and beat itself to death while making lots of extra noise without being all that much faster overall. Sure you'll get lower ET's and 60's will drastically improve but you'll surely realize the motor is not making anymore power to get you there by the time you're at the top of high gear. All about the balance of power and full complimentary combo of parts that gets you there.
Rob,Flatlander racing has those rods,k-1 012ad25625l & pistons are mahle sbf245040f06,I thought the weight on those rods was a little optamistic myself.I`m also well aware some light weight rods aren`t as strong as they should be,but K-1 is a good prdt. so I`m not worried.For the time being I`ll stay w/ the 1.6 rockers I have because of the 96872 crane v springs which are good to a .680 lift.However,1.7s push the cam to a .630 lift which would help but would put the springs close to coil bind & i`m going to go w/ those right now.I`ll also be using titanium retainers to reduce valve train weight so I`ll be OK w/ those springs.I`m also going run the howards lifters that use the .020 oil hole to help the cam live & use plenty of zddp additive.Crane says on flat tappets not to run much more than 320lbs open pressure or anyones cams will just not last that long,I`ll take their word for it being as they have been at this longer than any of the rest of us.Don`t have a mnfd. yet so I can do several diff. things,one of them is I don`t like the fact that none of the victor styles have no rear water crossover.With cast iron hds I`ll need more cooling,so I might just get the professional prdts one & have it ported.I know how much light bottom ends help a mtr,that`s why I want one,quicker revving,takes less power to move it,& easier on the blk.It`ll take a lot for me to get to the trk. next yr,just trying to build a simple base to get there.I don`t really want to go much quicker than a 10 flat,not interested in the politics of the NHRA to get certified,just want to go out & have fun.
Ok.. Chevy rods, now I get it. Holy crap those are super light even for an I-beam style rod in that length.. and much moreso for that H-beam design! I seriously wish they made similar ultralight budget rods for the shorter sbc 400 version in a 5.565 length. Then I could use a 427 piston and make a long rod 302 type deal. Was actually planning on using similar lightweight version to your part# except in a 5.7" length but don't want to kill stroke to squeeze them under my short deck to be able to do it. So, for now I'll keep it lower budget and spend the bigger bucks on my Al block buildup later on. Does your crank already have Chevy width rod journals?(.940 x 2 + side clearance).. or you'll just narrow up the rods to fit the Ford cranks cheek width?(.830 x 2 + side clearance). Because that would make them even lighter than they already are! Maybe get them well under 500 grams. Zoom zoom takes on a whole new meaning when it's all said and done. lol
Scat crank 4-351w-4000-6200-2,which is the 4in stroke w/ 2.100 chevy rod journal,& flatlander can get internally balanced for me,probably going to use the clevite h series bearings even though I`ve heard good things about Kings alecular bearings & they are cheaper,not a fan of Federal Mogul.
This section of the forum is called drag racing I would assume the guys that post here are interested in building a combination to drag race! if not it would be called high way cruising!
Nice. Pay the little extra cash for the coated versions if you can swing it. Not worth all that much for power but all the parent parts last longer and it gives you some extra margin.
