Who has the highest spinning 302 (or stroked 302)?

[StangJonGT]

I am getting back in the 5.0 game, and want to merge the best of the import world, the high rev count, with the best of the domestic world--the Mustang GT with a 302. I am trying to figure out what is available, what has been done, and what can be done. I am looking for no more than 7500rpms, but I know at that point the bottom end has to be rebuilt. So, who has done this or knows about this? Thanks--


Jon

 

[ashford]

well a long list of musts in in order for that speed out of a 302. steel crank, aluminum rods (or something strong and light) a good set of hyper-uetectic pistons, stud girdles, a solid roler lifter cam, very stout valve springs screw in 7/16 rocker studs aluminum roller rockers, and a set of really worked over heads for starters. im pulling a blank from there, i know theres more but that covers the basics. happy revvin

 

[FreeGT]

Why do you want to rev it so high? I'd rather invest in a stroker, and make some peak torwue at 5k.
This isn't directed towards you, but have you noticed the some people have this misperception that just because thier stang only runs 5,500 rpm, that it isnt making as much power as say an 7,500rpm integra? My 428cj Mach reds at 5K, but pushed 400hp. The reason these 4cyl cars rev so high is because thier stroke is much shorter, and have less displacement, so they don't consume as much air mass. On the other hand, v8s suck up more air, and just run out of "breath" faster.

I would like to see results of such a concept, as well as the hardware required to make it run.

 

[65ShelbyClone]

I am getting back in the 5.0 game, and want to merge the best of the import world, the high rev count, with the best of the domestic world--the Mustang GT with a 302. I am trying to figure out what is available, what has been done, and what can be done. I am looking for no more than 7500rpms, but I know at that point the bottom end has to be rebuilt. So, who has done this or knows about this?

The thing about that is its unecessary. Imports as you know only rev high to get good power numbers out of a small engine (so it looks good on paper, IMO). If you have a 5.0, you have the displacement so 7500rpm isnt required to make big power. If that much rpm IS needed to make power with a 5.0, then its not going to be fun on the street, just like a 200hp 1.8L with no bottom-end. This is all assuming the engine is N/A.

My advice is to start with a realistic power goal and build the engine to suit that. You just might end up with an engine that requires 8000rpm to make that goal. Then you'll be all set.

 

[StangJonGT]

FreeGT-
I understand that high power numbers are obtainable at lower rpms. I also understand that engine geometry has everything to do with why our cars breathe to 5500rpm and then fall flat. After that, our valvetrains and heads/intake can no longer move the required air to feed high rpm, so we start losing power. I want to reverse this. As for your theory on our engine rev range, I think you may want to read some more. No flames, but our cars were not built to rev that high, which is why they don't. They can be built to, however.

65ShelbyClone-
If you look at all the successful racing engines, the thing you are likely to notice is that huge torque does not come early. Quite the opposite, actually. And what I have discovered is, the best engine (for me anyways) is the one with a more linear power curve. I love low down torque, and the 5.0 hooked me while I was still nursing my permit. But also I love tractable, useable power through the rev range. What I am aiming to do is widen the 5.0's power curve to include a peak about 2,000rpm above stock, moving that fat torque curve up as well. This way, when I am punching 2nd out of a long sweeper, I don't have to compensate for my rear wagging. I am trying to combine two fun engine types; the high revving 4 cylinder with the torquey 8 cylinder, not having the compromise of either. That, my friends, sounds like fun.


Jon

 

[TIMMY2734]

That, my friends, sounds like fun.


Jon

So does having a turbo or blower that hits peak boost by 3500rpm. Unless you have a lot of money, id shy away from your rpm goal. You will definitely want an rblock/dart block as your base. I just wouldnt trust the stock block for what you have in mind. Then a nice lightweight, zero balanced rotating assembly will have you wel on your way. As for induction, im sure that any of the custom grinders, like Ed C will make a killer combo for you.

 

[EMW150]

I shift mine at 7,600. Anderson N-111 cam, matching springs, stock hydro-roller lifters. My bottom end is 28 oz balance and just tore down to refresh. The bearings look great which surprised me. 0 balance would be much better for the rpms though.

 

[RacEoHolic330]

C'mon guys that's nothing. My throttle stuck a while ago and my engine revved passed the 7k line on my tach. My digital tach read 7392 . Beat that! haha. Yea, it's time for a new engine for my car. The one in there now isn't doing so hot.

 

[sleeper89]

if you want a high revving 302....GO FOR IT

i think its a great project. i was considering a 7500rpm 302 myself but decided it wasn't worth the initial investment given my current goals. maybe on my next build.

if it were my engine i'd want to go with a zero balance on a forged crank. good rods, afm high rev cam (or similar). you have a lot of options open to you. some people even like to de-stroke their 302 when revving high to reduce piston speed...just some food for thought.

-steve

 

[88POSLX]

Like others have said... light components and good induction. You'll also need to increase compression. If you look at super stock cars, they should give you some clues.

 

[TrophyHead]

You might want to consider a de-stroker. Try a search on it. You'll rev the piss out of it.

 

[85_SS_302_Coupe]

Anyone ever drive an 8k rpm 289 Hi Po? THATS why it's fun to run high rpms...The thing is, on your average motor, you'll start to lose power after about 4500, but if you're running a good supercharger or turbo or even NOS, higher rpms are good for drag and even better for autocross. It'll be way cheaper to build a stroker that'll make the same power at 6k though.

 

[charlesw6954]

hey i saw a 5.0 or 347 but i think it was a 5.0 in the 5.0 mustang magazine they said that this guy's mustang made like 300-450 hp and revved to 8,500 rpms i was like dAAAAMMN! thats high revving.

 

[thumper460]

7500 +...... and still rocking...

We have been running the 289s and the 302's to the 7500 mark since the 60's!! But today there are a few things to change to keep the "buzz motor " buzzing!! Cool??[COLOR=DarkRed[/COLOR]

First... the block is ok!! ( I'd prefer the early blocks as they have thicker cylinders and stronger webbing in the mains...) Dont use the 5.0 crankshaft!! they will break between #1 and #5 journal. Get the early 302 crankshaft!! have a shop machine the oil slinger off the rear of the shaft ( used for the 2 piece seal) and now the crankshaft is a one piece seal unit and drops right in!! Rods... they are ALL GOOD!! the GT40s with the ribed caps are susposed to be better than the stock rods... but I have NEVER had the stock rod fail ( due to cap ends), just get ARPs installed and resize the big end!! polish the beams IF you want... again, I have never had failure on stock rods, polished or not!! cool??

Use the latemodel 5.0 forged piston with the light tension small reing sets... and of course BALANCE the assy!! I like to keep the far side of stock oil clearance on the bearings ( street time is hell on bearings) and I side clearance the rods to .025 , I do run the hivol pump !! Intake and heads and induction have to able to carry the RPM or the sound is nice , but the HP quite a long time ago!! 250-260* @ .050 , a tight LSA and the intake about 106 or tighter!! and your rocking!! the engine will live and give you tons of High RPM enjoyment!! Been there DOING that!!

Just me.........................

ThumperTpr

 

[63_Fairlane]

You will have to give up some low end torque. High RPM engines require big heads with big valves and a high lift cam. The larger openings allow more air to pass but they kill the bottom end power and torque due to poor velocity charateristics.

I would suggest an R302 block or an early casting and a forged crank if you are going to use this on the street and at the track... then again I have never built anything to spin that high.

 

[NoSloCoupes]

The 306 i just sold was more of a high rpm car...peaked at 7000rpm with shift points of 7500. Stock crank,stock rods(arp's with resized ends),stock block,stock lifters.

Another one i did was a 302..very similar motor, only more of a street car. Same exact shortblock, heads, cam...with an rpmII. 369rwhp(at 6400...shifted at 7000), 340+rwtq. Respectable #'s on both ends i think.

 

[331 cobra]

Why do you want to rev it so high? I'd rather invest in a stroker, and make some peak torwue at 5k.
This isn't directed towards you, but have you noticed the some people have this misperception that just because thier stang only runs 5,500 rpm, that it isnt making as much power as say an 7,500rpm integra? My 428cj Mach reds at 5K, but pushed 400hp. The reason these 4cyl cars rev so high is because thier stroke is much shorter, and have less displacement, so they don't consume as much air mass. On the other hand, v8s suck up more air, and just run out of "breath" faster.

I would like to see results of such a concept, as well as the hardware required to make it run.

Not true. The 1.8 liter integra engine has an 89mm stroke. That's 3.5 inches.

The integra does have a smaller, lighter piston than a 5.0 and more valves so it will breathe at high rpm. It is just better design and quality control that allows a higher rev limit.

A 302 will require a few bandaids to be reliable at those levels, but if all of the parts are strong enough (including the block), there is no reason a 5.0 can't survive at 8,500. Even a 331 should be able to do 8,500, but the margin of error get's a lot smaller because piston speed increases when you increase the stroke.

The main problem is finding an intake manifold that will support that rpm without killing the bottom end.

 

[maddog11]

Could always build the motor around a set of Coates heads ( I think that's how it's spelt), a well buiilt motor will rev to 14 750rpm - I have an article in one of my magazines about these...And one of the test motors was a 302. Only thing is I think the heads are $15 000 a pair... I'll have to dig up the magazine again to double check....Here is the article http://www.coatesengine.com/lookmom_noCamshaft.htm

 

[badcoupe]

The motor they pulled off the dyno before mine went on was a 302 SBF that made 1300+ NA hp and turned an amazing 14k yes you heard me right 14000 rpm. Amazing piece of machinery. Not much for longevity. Really big bore short ass stroke ie;less cylinder wear etc. The sound it made was unreal! BTW I turn mine 7800,396 stoker

 

[matty50racer]

why not build a stroker and rev it to 7,500 or more like me.

My motor should be making about 500hp on the dyno in a month or two and I will be shiffting it around 7,500. My solid flat-tappet cam also sounds just like thumper mentioned with 250/254 dur. @ .050, .592/.608 lift, 106 lsa installed on 104 ICL. I am using an internaly balanced, forged 3.25" rotating assembly in a girdled stock e7te block. Heads are mildly ported twisted wedge with comp springs, titanium retainers, and 7/16 stud rocker.

And I top it all off with a wiend tunnel ram and dual 450 holleys.