Budget 7500 RPM 302

good luck.......

I buzz mine to 7000rpms with a stock block, crank, rods and KB pistons. Its been together for 4 years now and still going. Over 500 passes on the engine so far. It runs low 11's N/A.

Here is my take on it. You would first need to remove your factory rev limiter via a chip, or tuning software in your computer. You will also need to make sure you have enough piston to valve clearance, and you will need to have strong/good enough valve springs to handle that kind of revving. Not to mention an SFI approved balancer is a good idea to keep the harmonics down, especially since stock balancers tend to break when revving past 6000 rpms, at least for multiple times.
But, what is the point of revving this high if your motor isn't making any power past 5800 rpm or so anyway? Im not sure what you have, but a stock motor just doesn't make much power past 5800 rpm or so. You'd need forced induction, or a high breathing motor to take advantage of 7000+ rpm. There was a guy with a stroked 5.0 with higher compression revving his motor around that rpm...ran very good numbers actually.
His car should be on the anderson ford motorsport website under customer cars.

good luck

Dan

youre going to need pretty big heads and cam and intake to power it past 6k let alone 7 grand

It wont be cheap.... really no way around it.
-Your going to need top spend some money on a lightweight piston. Wouldnt trust a heavy trw slug.
-I dont know if thumpers head will rev it as high as you ask.
-Seeing as you want it for autoX, id imagine youd destroy the block in no time flat... Going the 1/4 mile would be one issue, but this is probably asking too much. 2 things that kill the stock block are RPM's and harmonics. 50oz balance and 7500 rpm in the stock block going through a road race course may not be the wisest of choices.
-valvetrain, you know what the stuff costs and it all adds up very quickyly.


What do you consider 'relatively cheap'?

Ok, you want high revs and for cheap then heres one way. First, switch to carb because it costs less and run at least a 750 due to the rpms. Use a Vic Jr. intake, any stout cam and since we are roller your half way there. As for heads, do a Clevor conversion using Cleveland 4V heads with lightweight or beehive valve springs. Honestly, I wouldnt use a stock bottom end due to oiling issues, weight and proper balancing techniques from the factory. A good clutch and SFI balancer are a most and you can get an SFI balancer for $100. Thats your cheapest bet, and no way will Thumper's heads flow that much rpm. You need a good size valve and at least 185 cfm intake runners. Since you need a big valve, you'll need to ditch those stock pistons or notch em. Good time to go with something light and if your going NA then it doesnt need to be forged and expensive.

For a stock 5.0, the words budget and high-revving don't go together.

First It can be done. Second, if done correctly it's a mean engine that'll seriously lay down the rubber and would be a real screamer down the track.. However though, thirdly - read the first line in this post

Paul - I think the best money you can spend is to invest a few bucks with Buddy Rawls and have him model some different cam/heads/intakes/exh. set ups. You'll need to be sure that the combo you select will handle the flow at those revs, and that the peak is where you want it to be. And it's gonna take a lot of head/cam to peak at 7000. As for "budget", well, it's only expensive if you can't afford it. Can't wait to hear it. Oh, for the revs/power you're talking about, I think static compression ratio is gonna need to be a good bit higher than stock.

Talking aluminum then I think your best bet is either the Vic Jr heads or the highports. They both sport the flow you need and they are both under $1400. Thats a good deal considering youll pay around $1700 for AFR 205s which are in the same class. Go with the Vic stuff since they have matched combos already figured out by the edelbrock engineers. Edelbrock claims the Vic Jr. package peaks at a little over 7000 rpms with a 302. You'll need new pistons for those valves and to lighten them up so best to rebuild everything. Mine as well go with a long rod 302 since they can really rev and you need new pistons anyways. And like Yount says, you'll need more compression. Edelbrock's combo made their power with 12.8to1 comp.

Intake/exhaust duration Paul only make sense when viewed in the context of the flow capabilities of the heads/intake/exhaust. Dual pattern cams work well (more exhaust duration) when you've got a flow deficiency, usually in the head, on the exhaust side. The Ford Racing X and Y heads are this way - their flow is intake biased, and they need help in the form of more duration and/or lift from the cam on the exhaust side to make up for the lack of exhaust flow in the head. So you see, you really need to pick heads/intake/exhaust system that are capable of enough flow to support your HP requirements, and then select valve timing events and CR such that the power peak occurs where you want it to. I firmly believe that without a professional modeling it for you, any cam choice is gonna be purely a guess. Valve timing events are what need to be selected - not lifts and durations.

Here's a link regarding rod length/stroke ratios and the implications. It's aimed at strokers, but the principles are the same. Going with a longer rod will give you a higher rod length/stroke ratio. As you'll see, the pros of a long rod engine are in your favor if you're building a high revving small block. But it's probably not a huge advantage. For the money it would cost, you'd be much better off getting Buddy or Ed to model things for you to help you select heads and cam. I'm a broken record. Here's an excerpt:

Pro:
» Provides longer piston dwell time at & near TDC, which maintains a longer state of compression by keeping the chamber volume small. This has obvious benefits: better combustion, higher cylinder pressure after the first few degrees of rotation past TDC, and higher temperatures within the combustion chamber. This type of rod will produce very good mid to upper RPM torque.
» The longer rod will reduce friction within the engine, due to the reduced angle which will place less stress at the thrust surface of the piston during combustion. These rods work well with numerically high gear ratios and lighter vehicles.
» For the same total deck height, a longer rod will use a shorter (and therefore lighter) piston, and generally have a safer maximum RPM.

Con:
» They do not promote good cylinder filling (volumetric efficiency) at low to moderate engine speeds due to reduced air flow velocity. After the first few degrees beyond TDC piston speed will increase in proportion to crank rotation, but will be biased by the connecting rod length. The piston will descend at a reduced rate and gain its maximum speed at a later point in the crankshaft’s rotation.
» Longer rods have greater interference with the cylinder bottom & water jacket area, pan rails, pan, and camshaft - some combinations of stroke length & rod choice are not practical.
To take advantage of the energy that occurs within the movement of a column of air, it is important to select manifold and port dimensions that will promote high velocity within both the intake and exhaust passages. Long runners and reduced inside diameter air passages work well with long rods.

http://www.victorylibrary.com/mopar/rod-tech-c.htm

No problemo - it's past time for a get together; I always enjoy your company. Headed over to Charlotte to visit a good friend who's coming down from DC to watch/help his 12 year old son go kart race in the infield track at the speedway. Should be back sometime Sat.

TnPaulMan said:

Well, I know it wont be that stock. But I figure I can spend about 4K and do the work my self and get that kind of motor.

Click to expand...

Things must have changed, 4 grand isn't exactly a budget finance to me
You should be able to reach your goal barely with that type of finance. As Mr. Yount said, buy parts that would meat your engine's goal(s). The biggest key is to get everything to work together in the most efficient means possible. Lighten the rotational mass on the internals, get some deep-breathing cylinder heads, and high-volume intake manifold and/or carb, and slap a cam in there that ties it all together yet at the same time will meet the demands that all other parts of your engine place upon it. The cam is the heart and sole of an engine and the timing is the beat/rythm - get them in sync as well by means of the best possible choices you can make for your combination, and you've got your goal