Hey guys i have a few questions for you guys. First of all, I'm not the most knowledgeable person about Chevy 350's, I'd just like to pick some of your brains about this, because I know the knowledge on this site is unbelievable.

First of all the 350 I have is bored .040 over, the previous owner said it was 11:1 compression and 4bolt main. It has a comp-cams .507/.507 lift 292/292 duration. Comp-cams #12-213-3. The heads don't look like anything special, I haven't pulled the valve covers.
It has a Demon 630cfm 4 barrel street demon carb and roller rockers.

I haven't really reved this motor up, only to about 4,000rpm. It seems to be making alot of power. The previous owner said it was 400hp, although I don't know, the car really seems pull great once you rev to 3,000ish.

1)How high can I safely rev this engine and it stay together? 5500-6000ish?? Whats the safe-zone usually on an uknown engine. Or can you guys give me an approximate redline from these specs???


2) Lastly, the car has 3.73 gears and a muncie m21 tranny, hooker super comps and a world products dual plane intake. What do you think this car would do in a 1/4 mile, roughly

If it truly is 400hp then with the proper tune and set up you'd have a low 12 sec car in the 1/4. As far as red line or shift points even a stock 350 in good shape can handle 6000 from time to time. Although without knowing the condition of the motor I wouldn't suggest much over that. I mean spinning it a time or two up to 6500 may be ok. As far as what you should actually shift at for a best et. is another story. You don't always want to shift at max. rpm. In you're case you probably will want to shift at a lower rpm because that's where your peek torque will occur. My dyno sim. CD is packed away already, but maybe someone else can chime in with an est. hp and torque curve to give you a better idea on a projected ideal shift point, or at least a good starting point for your first few trips down the 1/4. I can tell you a good friend of mine used to run an almost identical motor combo in his 70 Nova. Only real differences where he ran a Vic. jr. ,750dp, and 4.11 gears. And his best times of around 12.2X-12.4X came from shifting at 5900. Now keep in mind the bigger carb and intake ran the power curve up a little though to.

The motor is relatively new, it was put together by the previous owner in 2001, with around 1,000 miles on it. Sorry I forgot to tell you guys that.

400fbird,

Your 350 is very similar to the one in my current 1969. The prior owner had someone build the engine. I have a monster sized Autometer tach with a shift light. I hate that thing!! The guy was making it into a drag car before I bought it. He had a full spool in it. I saved it from being tubbed, backhalfed, caged etc. Your cam specs are nearly identical to mine. I think mine is .292/.292 w/ .524. I run 4:10 gears w/ a Super T-10 4 speed. The carb is a Holley 750 dbl pumper w/ mechanical secondaries. MSD 6AL box w/ MSD distributor. I think the compression is 10:1 or 10.5:1. This car is not as fast as my old 1969 which had a 500 HP 396 in it. However this car has some nice bolt on Edelbrock aluminum heads while my 396 had regular cast iron heads. Still hough I'd take my old 1969 over this current project turd anyday!!

I would say if your car can hook and it has 400 HP, then mid 12's like a 12.6 should be easily doable. My old '69 ran high 11's/low 12's on it's best day and that's if it hooked up. I used to race my friend's Suzuki GSXR 600 and that was a high 11's/low 12's bike.

As far as shifting you should be in your power band anywhere from 5,200-5,800 RPM's depending on your ignition, carb, heads, bottom end, rear gears. Mine likes the 5,600 RPM range although I've gone to 6,500 and it held. Don't go there!! The seller told me he had it built to hold at 7 grand. AGAIN, DON'T GO THERE!! I bought the car last summer but I hardly drove it since September as I've been working on it now for several months.

I'm not Mario Andretti or Dale Earnhardt Jr but 5,500- 5,800 RPM should be ok. I would say 5,600. It's scary but your '67 sounds alot like my current '69. I haven't taken mine to the track, but like yours it pulls strong around 3,000 RPM. Enjoy your car & Good Luck!!

Forged internals..youll float the valves before you have spun it to high.
DO NOT DO THAT.
Cast internals.. stop around 5500 when racing, around 5k when playing on the street. Launch around 3500 and shift 1-2-3 at 5900 by then you should be close to tripping the light if it hooks good enuff...if the internals are cast let the engine idle after EVERY PULL to let the bottom end cool down enough or youll warp/twist the crank. JMHO thats what I would do.

Warp/twist a cast crank?? Never heard a that one, wiskee??

Now BREAK, yes! cast crank if ran at the torque peak under a severe load for a long time, break indeed!! Like a Big Boat or a loaded Dump Truck pulling ALL the time..

I figure a cast bottom end should be good for 6 to 6500 OK, imho....

Not all the time mind you, but occasionally(Sp?)..

400bird,

What gas you running in your engine?? I ask b/c I DO figure at 11 to 1 you will want good gas in her............

pdq67

thanks for some of the info guys. I don't really plan on abusing the engine. Probably keeping it under 5 grand. Just because I'm pretty cautious, I just wanted to get a ballpark range about this motor.

I'm still trying to learn, so any bit of info from you guys helps.

pdq67: I'm running 93 octane with no problems.

I turn 7,200 with stock bottom end (even the rod bolts) and I built the motor two septembers ago as a "quick" fix to keep the car going. 6,000 should be nothing, I have way more faith in these little motors than ever before.

just drive it cautiously at first, and just kind of keep pushing it harder as you get comfortable with it. you will learn it's limits and what it likes over time.

Warp/twist a cast crank?? Never heard a that one, wiskee??

.......

I have seen a few cranks pulled that when looked at closely you could see the counterweights werent square with crank centerline, in-a-sence, we caught it before the break. Its actually kinda neat to see, all the main berings have a cool looking blue color.....

Diddo Novaderrik...as you drive it you will 'learn' its likes and dislikes. Chevy engines are real good about letting you know their likes and dislikes...

I really don't like the "dislikes" part!!!

I really don't like the "dislikes" part!!!

Chuckle, ....Chuckle....:D

Knock on wood, I've had good luck wih 350's, a 327 and a 396. My friends had good luck with 427's and the 454. I can't say the same for that piece of garbage 305 that was in my 1984 5.0 H.O. Z28. The cam went flat at 92 or was it 93k miles. I despise all 305's. The 305 is nothing more than an overpriced boat anchor. I also liked the Chevy 307. That was a reliable engine as well.

wiskeesour, I totally agree with what you said in post #5

South Side, I take it you dont like 305's?

South Side,

Please come back and tell us how YOU really feel about the old 305's.........

He, he!!

pdq67

I don't know about you guys...but I'm in the process of building my small block 350 bored out 4.030 and I'm plannin on having a redline around 7200 rpm's. You guys out there shifting your 350's at like 6000 and lower...what's going on guys? The 350 can hanlde more than that. However, I do have all forged internals and splayed caps so...maybe I'm a litle better off than most setups out there. Of course my engine will basically be built as strong and tough as the dirt track engines in many sprint cars pushing around 7500 and 8000 rpm's in their 358's and 410's. I don't mean to sound like an ******* just I don't know...if your'e gonna race a 350 and plan to win against competition...you need to shift a little higher than 6k. But yeah...even though my engine won't see too much drag time...it'll still be pushing around 7000 rpm even after I set the rev limiter on it.

305`s have some great uses...if you need to hold a giant piece of paper still...if you have a really big kite that will pull you away...if you need a place to chain your dog...to tie behind the car at a redneck wedding...if you need something dragged to the bottom of the lake quick...(the wife didnt like that one...lol...)if cast iron ever becomes a desireable commodity...

and ps, if your cam and intake wont support more than 5800 rpm, why would you go past that???just cause a motor will freespin to 9800 rpm doesnt mean it is making power tghere...just the contrary, you will lose power past your peak hp point...in addition, depending on valve springs used, the valves will float, and potential damage can occur at much lower than 7500 rpm..bigblocks rev much lower, generally, because they use much larger valves...heavier valve trains are much harder to control, so extremely large springs are used...much higher spring pressures are neweded to control valve float, so much better, and more expensive i may add, lifters are used...no matter what engine you run, a red line isnt where the engine will blow up...only where the engine runs out of "lungs"...spinning it up past that only increases engine wear unnessecarily...

Again forged internals make about 2000rpm difference. Unless you are the only v8 2-stroke in the world.....7200 with forged internals is close to all a Chevy can take and still make power. Any harder than that you need to remove weight, I.E. the two rear cylinders. Believe it or not.

Hey guys i have a few questions for you guys. First of all, I'm not the most knowledgeable person about Chevy 350's, I'd just like to pick some of your brains about this, because I know the knowledge on this site is unbelievable.

First of all the 350 I have is bored .040 over, the previous owner said it was 11:1 compression and 4bolt main. It has a comp-cams .507/.507 lift 292/292 duration. Comp-cams #12-213-3. The heads don't look like anything special, I haven't pulled the valve covers.
It has a Demon 630cfm 4 barrel street demon carb and roller rockers.

I haven't really reved this motor up, only to about 4,000rpm. It seems to be making alot of power. The previous owner said it was 400hp, although I don't know, the car really seems pull great once you rev to 3,000ish.

1)How high can I safely rev this engine and it stay together? 5500-6000ish?? Whats the safe-zone usually on an uknown engine. Or can you guys give me an approximate redline from these specs???


2) Lastly, the car has 3.73 gears and a muncie m21 tranny, hooker super comps and a world products dual plane intake. What do you think this car would do in a 1/4 mile, roughly


I had the same cam (Comp Cams 292) in my 327 +.040 and a few diff. sets of double-hump heads. I routinely revved mine to 6500 in 1st and 2nd gears. I did have ARP rod bolts. That's the unknown strength equation of your engine combo. In racing, my heads just didn't really flow up at 6500. I thnk you should stick to 6200 on that unknown engine.

Do you know what heads you have? If you pull off the valve cover, you should see it embossed there. I or someone else can try to look them up.

If you're engine, traction and gearing were dead-on, you'd have a 12 second car but I think realistically you'll find yourself in the 13's.

I have a ton of receipts from the engine build. Maybe I can find out what kind of rod-bolts are in the engine.

I might pull the valve covers off, but I've had bad experiences with the 455 firebird motors getting those valve cover gakets to seal again after removal, you know what they dont if it aint broke dont fix it.

i apreciate all the information guys, i really do! Thanks to everyone who chimed in.

You need to see what your valve springs are to make sure they wont float and check your rod bolts but if he built it im sure its arp and the cast stuff should be fine to 6500 and with your cam i would say the peak would be around 7000 but im not sure what the .050 duration is. Everything should be balanced but your carb and your heads are probably holding you back depending on your heads. I have a 383 that will be spinning to about 7000 but its forged and balanced.

You need to see what your valve springs are to make sure they wont float and check your rod bolts but if he built it im sure its arp and the cast stuff should be fine to 6500 and with your cam i would say the peak would be around 7000 but im not sure what the .050 duration is. Everything should be balanced but your carb and your heads are probably holding you back depending on your heads. I have a 383 that will be spinning to about 7000 but its forged and balanced.

Update, bringing this thread back from the dead. I looked through some of the recipts and the car does have ARP main bolts. So I guess that is a good thing. Also I have identified the roller rockers as Harland Sharp Roller rockers.

If you're engine, traction and gearing were dead-on, you'd have a 12 second car but I think realistically you'll find yourself in the 13's.[/quote]

I agree with above person. I think low-to-mid 13s is spot on (assuming traction and take-off go well and you shift the car appropriately). Check out the link below (50 top muscle cars in 1/4 mile - very cool page by the way) and tell me that you think this car we are talking about is more stout and putting out higher hp & TORQUE than a lot of ones that were running mid - high 12s, had big blocks and were likely driven by professional test drivers to obtain that time. Also keep in mind that the HP specs for cars on this link is way off as they are quoting manuf. advertised hp. C'mon, let's keep it real - this relatively mild 350 that tops out at around 5,500rpm is not gonna do low 12s w/o a nitrous shot or Godzilla blowing on the back end of it. :noway: I'm not at all dissin on your engine (which actually sounds very nice) but just tryin to portray a realistic expectation for when you actually go to the dagstrip and race it. :)

http://www.earlham.edu/~byersjo/top50.htm

yea thats what i was thinking prolly a solid 13 sec car. Although I dont think i'd ever beat on it enough to find out lol. my friends call me a pussy foot.:noway:

Whiskee,

I wanna say SY1 has talked before about blue main journals when using spacer bearings in high rpm SB's.

pdq67

That cam should pull well through the gears to 6,000-6500 rpm.

A decent 350 will spin past 7,000 without problems.

Lawnmowers can spin past 4,000 rpm.

Can you contact the previous owner and ask whether the bottom end is forged and where he shifted it? It sounds like the previous owner spent $ on good stuff (harland sharps, world intake, super comps) so I would guess forged. Of course that is only a guess... Does the car still pull at 5000-5500 or start to go flat? You'll get a feel for where it wants to shift. I built my camaro to spin high rpm and have run it to 8k (when I'm mad at it) but I think it runs faster in the 1/4 if I shift around 7200-7400.

Oh yea, Since you are rowing a 4 speed, get a Rev-limiter.
An Adjustable one, a 2-step one with various chips.
A tell-tale tach will tell you how fast that motor can spin if you miss a shift...

Heck, my old small journal cranked junk301 w/ the little bitty, -097 Duntov solid lifter cam and 11/16" rod bolts saw 7500 rpm when my points would hold!!

And I know there were many a '67 302, Z-28 engine that saw above 8,000 rpm's b/c you could tell them b/c the valves would be bent b/c the valve springs wouldn't hold rpm's like that for very long!!

pdq67

yea i've heard a video of a sbc revving to 8 grand, it was music to my ears.

The highest I've revved my motor to was about 4800-5000. Boy is is a sweet sound.

I've got a decent set of Vortecs, good valve spings, Pro Magnum roller rockers and a Comp Cams XE-268 on a $400 350 short block I purchased freshly rebuilt (that I don't really care about) with a 6,500 pill in the MSD 6AL. It pulls hard to 6,500 rpm and seems completely happy doing it.

The OP's issue is that he doesn't know what's in the top end. I'd be much more concerned about valve float than the bottom end letting go.

I shift my all-cast (with stock reused rod bolts) 350 at 7500 when I race. It puts a smile on my face, I'm funny that way.

Two thoughts on RPM limits:

1) Its not only how high you rev, but how long you keep it there. Drag racing is really pretty easy on an engine versus land speed racing (or boating or dump trucking). Some of those super stock crazies even run there oil pans dry during the run to make more power!

2) In racing, valvetrain problems are far more common than bottom end problems. Your mighty mouse will most likely hit valve float long before the crank snaps.

Piston speed of a 302 at 7500 is about like a 350 at 6500.

Good Luck!