So I was talking to my mechanic about a new motor for my '86 z28 and he mentions this de-stroked 307 he and his race crew built in 1995 for some certain nhra class (dont remember what he said) Anyway this motor did an 8 second quarter mile at 165 mph in a 1200lb race car. It ran on alcohol and launched at 7,500 rpm and shifted at 10,000. This thing sounds ridiculous, and he still has all the custom made aluminum rods and the custom made crank. He told me if we swapped out the roller cam for something smaller he could put this motor in my car, and make it streetable for $3000 while still making around 500 hp with racing fuel. Sound like a good deal??

 

Sounds like your gonna need a TON of gear. But racing fuel isnt that cheap if this is gonna be a street car.

3000$ for 500 hp would be sweet and high revving cars can be fun, but itd be nice to see a dyno sheet before you buy it.

 

I do want to drive it on the street but definately not on a daily basis. Anymore, racing fuel isn't a whole lot more than 91 octane as far as price goes. I also plan to talk to him about the best stall and gear ratio for this motor.

 

gearing will probably be an issue.. if you plan to shift anywhere around 8k, you will need a stall of around 5k.. and a gear of more than 4.56.. not very good for street.. you will also be cruising the highway/freeway at post 3k rpm.. not good for any sort of gas mileage.. and if you have to run race gas, thats gonna suck.. you cant let race gas sit for too long..

i would just invest in a 383 or something and get 500hp on PUMP gas.. heck, just make a 415, 421, 427, 434, etc.. easy 500hp.. no need to change gears and no worries about burning a tranny or converter from ridiculous stall speed.. just my $0.02

 

Given that your Camaro weighs almost 3X that much, I don't think you'll like the results.

 

The 307 has the bore of a 283 and the stroke of a 327.

A "destroked" one would likely come out to a 302 or 283, depending on what stroke, and if it was stock.

Think about how much that would cost, compared to a 383 or a 400. Would you REALLY get more bang for those $$$$ by going that route?

How many of these motors have you seen in real-world street cars (3500 lbs or whatever)? Given any thought to why?

You do realize that the last time the 307 was made was in about 1972. You're maybe too young to remember this; but do you have any idea how long it took 283s, 307, and 327s to disappear from the racing scene, once the 350 and 400 became widely available? Well, I do.... because I was there. And I'll tell you: it took about ONE season of getting your a$$ whipped by somebody with a bigger motor that for every $$$ you spent, they could spend less $$$ and beat you. That gets REAL OLD, REAL FAST.

Are you in that class? Do you know what that class IS? Well... it's one of those "weight to CID" sportsman classes. Meaning, if a 302 let's say is legal at 1200 lbs, then a 604 is legal at 2400 lbs, and a 906 (!!!) would be legal at 3600 lbs. It probably has weight and/or CID limits though, designed to fit a certain style of car. like, 1200 lbs min, 5.0L max, or something like that. Making his combo percect to max out the class.

Do you think a 302 in your car would run a credible race against a 600+ in an otherwise identical car in the other lane?

All in all, while it might be the ideal way to go for a guy that's in that class, it's not a very sensible option for a street type of car.

 

I understand there is better motors out there, but who is selling 500 hp motors for $3000? It doesn't have stock GM internals, all custom. steel crank, aluminum rods, it's actually a 304. The intake has all the nitrous bungs welded in, so I could always run nitrous if I wanted to, and who cares if I haven't seen these motors in any other cars? maybe it's because nobody wants a street car that radical? Or maybe it's because they spent over $15,000 to build this 304.

 

Yeaaaa, that must be why. Well, if you're set on it, good luck to you. Unfortunately threads just like this pop up entirely too often, yet we never see the guys months later saying how great an idea it was... BE THE FIRST!
Prove us all wrong! I wouldn't mind having my face rubbed in some humble pie. Give'r!

 

Just do it with YOUR money; not mine.

BE SURE to come back and tell us how it is when you get it all done.

 

cubic inches=street fun less rpm. dont be fooled into thinking 500hp is at a street rpm because it wont be with the cubic inches at hand. rear end and tranny wont take the abuse=$3000 500hp really is very much more real world dollars. Do it right research all your options and think logically how you want to spend $8000.00 minimum.

 

Oh damn, i just about fell off my chair i was laughing so hard when i saw this!!!

So lets say you put this 500hp motor into your thirdgen and take it to the strip. what do you think your going to get out of it?

Its definately not going to be an 8sec car, or anything close. More like a mid 12sec car.

Then to top it off its a total POS to drive on the street and gets about 2mpg because your cruising main street @ 7000rpm....


This motor is definately NOT the way to go!

You would be alot better off dumping $3g into an old 350 block, stroke it out to a 383 and you will be alot more satisfied. A 383 can easily make the same HP numbers with GOBS of torque(torque is what makes it fun) in a street friendly RPM range and still run pump gas.



But hey, its all up to you, its your money...

 

this is just what i've heard but dont you have to change out aluminum rods once a season.. or more.. not good for street useage also.. but what do i know, i never used them.. nor did pretty much ALL the people on TGO..

that motor is gonna make jacksh!t for power under 5k.. the rotating mass is so light, you will have no torque.. and its just gonna be a bitch to drive.. even with an auto..

 

We used to make aluminum rods at Manley. They're good for 75-100 drag strip passes and they're done. That's 25 miles.

 

hmmm, okay so you guys pretty much talked me out of it, even though I think cruising main street at 7000rpm would be tons of fun. The same guy also has a 350 making around 425hp with 10:1 comp. I guess this would probably be a lot more street friendly. btw the rods he showed me were manley.

 

Perhaps - for about 37 seconds.

Not trying to throw you a ration of crap, but I had to re-read this when I first saw it, because I kept thinking "WHO in the hell would spend money on a 307, and why???" Has he been your mechanic for a while, & built up a good track record???

Seriously - pay attention to what the others on here are saying, a lot of the time it comes from hard-earned experience. You'll have a lot more fun with the car if you throw a 327, 383, 400/406 or even a decent 350 in there. You'll also spend less cash & less time fixing broken valvesprings, drivetrain parts, etc.

Good luck.

 

Who even makes valves springs for a SBC that can handle 10K rpms? and not destroy other valvetrain items?

 

Here Ya Go.
Check out the seat pressure on the 1248-1250 springs. Requires roller cam and REALLY strong rockers.

 

good god!!! 395lbs seat pressure @ 2.250"!!!! thats 3 times as much as my solid flat cam springs.. but if its needed, thats cool..

 

truthfully this is a real funny thread for an engine builder like myself.. Bud let me give you 2 very usefull tips... Stay far far away from that so called "mechanic"..... And a fool and his money are soon parted. Don't be his fool, do your own research and you'll see just how much water that 500 hp, 8 sec de stroked 307 has.

A "de stroked" 307 is a 283 cid engine

To make 500 HP that would be 1.766 HP per cube... With todays better heads, parts and know how. On N/A engines we shoot for 1.5 HP per cube and hope for atleast 1.30 HP per cube. Most engines only makes about 1.10 HP per cube though.

There's no torque at lower to mid RPM's with the short stroke enines.. If that engine was true then you would need to run it in the 7500 min to 1100 rpm power band.

You'll need atleast 5.40 gears, 6500 min stall converter. Valve springs would need replacing after every handfull of passes.

The alum rods are junk now and will need replacing.

To get that type of power and rpm out of a 283 engine it will need 15 or 18* race heads, offset shaft rockers, etc etc.

Just build you a 355 or 383 for $2000-3000 and have you a true 400 to 450 HP engine with good manners, good torque, will work with milder gearing and stall (3.23 to 3.73.....2500-3200 rpm stall) Run in the 1500 to 6500 rpm band