Lightweight flywheel on a SBC

[71elcamino]

What are the pros and cons of using a lightweight flywheel? im building a ratrod, and im wanting something quick revving and snappy. but what are the pros and cons of having a lightweight flywheel? i have found some billet steel flywheels that were 10 and 12 lbs. i want something that revs quick, it'll sound tough and jump quick. opinions and input? thanks

 

[PA41]

In a light car with plenty motor it's pretty sporty. It makes for quick throttle response -up and down. They'll rev quick--sometimes too quick--I've eaten a valve with a light flywheeled SBC from over revving. Sometimes the car won't idle too good, and pulling from a dead stop can be a little abrupt.

For racers they are great, for a cruizer they might be a little too much though. Just depends on what you're after. Ya prolly need to do it once to just see... Thats what livins for..

PA41

 

[Got Rust?]

Just my two cents
lightweight does give quicker start times, but, and this is a problem, there is no, or little "coast", meaning the car backs off quick when you ease up on the go button.
for me ,,,,,drag car yes, street,no, track, where I ran no, need to ease into corners, or around curves, without your face hitt'n windsheild, or having the back end come around.
just me.

 

[Screamin' Metal]

That flywheel spinning gives your motor alot of torque....thats alot of mass spinning.....if your gonna do the super hot street thing.... you could run one, gonna loose the torque. Revs will be alot quicker.
For a regular hotrod, I'd say the moneys better spent in some coolness factor....like chopping your top or channeling or Z'ing your frame....[P[
If you want quickness...thats what horsepower and gears are for....I build alot of drag motors....thats where the alum flywheels were used. Believe it or not, if your making the horses, its best to hold a steady high rpm and make your horses, and use that formula to pull against your weight with the gearing. The good quality steel flywheel once it has 600 or so horses behind it spinning at 7800 rpm or higher....its takes alot to slow that puppy down....
You want to gear that car so the rpm loss is minimal between gears (good flywheel effect), and you want to go thru the light pulling hard agianst the redline.

 

[71elcamino]

never thought about it that way. makes complete sense. whats it cost to have a top chopped, say 4 inches?

 

[Screamin' Metal]

Do it yourself for a little of nothing, some sheetmetal/ bracing, welding wire some gas and a whole bunch of elbow grease....you'll learn alot and all of us can talk ya thru it....plus doing it yourself....you'll have some braggin' rights....[P[

 

[Got Rust?]

one SawsAll blade, or "clean" cutting type tool
cutt'n torch, if ya ain't putting it back on

 

[Got Rust?]

wait
stop,
just read your post again, refer to other guy's answer.
turn off the torch!

 

[Screamin' Metal]

Quick revs and snappy performance, use a 327 or a 283. Even the 265's are quick little rev'ers.....with these little motors, put a alum intake, a decent carb, a little cam and some headers....the little things will scream![P[

 

[Screamin' Metal]

And oh yes.....the 302's....anything long stroke is gonna rev slower....[P

 

[71elcamino]

so how about a '69 307? thats what im using as a powerplant, i bought it from a friend for $50 back when i had my 71 elcamino. i wasnt sure if it was an original 307 or 350 car so i bought it, he threw in a set of double humps. when i sold the elcamino i was just gonna get rid of everything sold the heads ( true 202-cast #462) and now i kick myself for selling them. but the 307 is in good shape and im gonna put rings and gaskets in it. is this a decent motor to run? im gonna put a cam in it, and port and polish the heads.

 

[Screamin' Metal]

good little motor.....it isn't a 325 horse 327....but a good solid, dependable sbc....[P[

 

[71elcamino]

cool. good to know. what are some easy ways to pull power? i know heads, aluminum intake( i have a cast #458520 aluminum vette spreadbore that im gonna have ported to match the head work and put an adapter to use a squarebore carb) cam. id like to get alil over 300hp. maybe like 325-350. what are some options i could do on the more inexpensive side to pull hp? get some double humps? and will they literally give me 300hp? and what about vortec heads? i can get a carb intake for them for cheap, and i know somebody with a set that came off a 350.