86IROCracer89

ok i have a crate 350 im caming it and putting on an hsr next week and i had a question about the rev limit. i dropped this engine in last spring and the more i look at this the less it makes sense to me, but maby im just over thinking it. GM says the redline for this engine is 5100. my question is why so low. looking at the dyno sheet you can see max hp is at the red line and is still climbing and the TQ hasnt even dropped under 300 at that point. so that rules out that its not making power and to leave it at that. so my question is did they do this due to engine durrability. it only has cast internals, nothing is forged. so im wondering where you guys think this engines breaking point is. i would like to rev to 6k but i dont want to be driving around a $3500 hand grenade either.

heres the engine stats, http://www.gmperformanceparts.com/En...P&sku=12499529

thanks guys

Atilla the Fun

That's a 7.8:1 engine with an all-wrong cam, and smog heads. If you just put any stock exhaust manifolds on it, with an Edelbrock 2101 or a Weiand 8004 intake, it will be all done by 5100 rpm. Swap in something like this:
http://www.compcams.com/Cam_Specs/Ca...x?csid=96&sb=2
and use the correct valve springs, plus use headers and a 3" exhaust, it's perfectly safe spinning the thing to 5500, as long as you're not keeping it up around 5500 for more than a couple seconds at a time.
You want 6000 rpm? You'll need better heads, a better intake, and even more cam. The stock bottom end will survive this for a blast down the quarter mile. As many blasts as you want, really. Because you're not at 6000 for more than about a third of a second.
If you want to hold 6000 or go past 6000, you'll need better rod bolts at a minimum. Cast pistons don't like going past 6000, either. And the factory didn't balance the crank precisely enough for that sort of usage.

86IROCracer89

like i said its getting a new cam and a holley stealth ram next week, i got headers lined up and have a 3' cat back with a gutted cat, planning on a set of 2.02's as soon as i get more money.

regal301

what are your plans for this car..................if its a daily driver street car i would build it to stay UNDER 5,000 RPM.

the stress on that motor from repeatedly screaming it past 5k is not going to be worth any power you think your missing out on.

Atilla the Fun

Even if you 2.02 these heads, and mill the heads 0.035", and use Fel-Pro steel shim head gaskets, you're still under 9:1, and still not flowing anywhere near a stock Vortec 350 head. don't put any money into these heads. You're better off buying #416 heads, having them cut for 1.94s, and porting them yourself.
Either get vortec heads, or your power will never peak higher than 5500 rpm. But with the extra compression of the ported 416s, it'll be better than 2.02-ing the heads that came on this engine.

Atilla the Fun

Oh bull.

86IROCracer89

when i said planning on 2.02's i meant brand spankin new aluminum heads from summit, http://www.summitracing.com/parts/EDL-5073/

been looking at these for a few weeks. i think i might just build it to run to 5500. but when it runs to 5100 as is i dont see how an extra 400 rpm is going to be "screaming". the extent of my mods are going to be the hsr, cam, heads, headers, a manual at somepoint, and possibly true duals in the future. i just want to be sure i can run it to that point as much as i want without my crank falling to pieces or a rod having an affair with the cylinder wall. i just dont want to have to rip the motor out and rebuild the bottom end mid summer. the car has sat long enough this winter as is.

as far as this car goes its a daily driver in the summer. its going to see some track time, and whatever tuner nature randomly throws my way on the highway. other than that im fairly nice to this car.

EvilCartman

iTrader: (1)

Build it and run it. If it flings apart, you'll know what needs to be upgraded.

86IROCracer89

im only 21 and dont really have enough money to fix the bad things that can happen when it just "flings apart". i just love driving this car too much to just have it sit around when i transfer everything to a different block after the crank shreds the bottom end or a rod gets thrown threw the cylinder wall. if i wanted to just build it and run it till it falls apart i wouldnt be asking these questions......

dimented24x7

iTrader: (2)

I dont think it will grenade from being run up to 5500 RPM. I currently have just the shortblock of that engine. I bought it for $800 when it was still available, and GM lists the redline as 5500 RPM. The rev limiter in my PCM set to 5600 RPM, and typically run it up to the rev limiter when shifting at WOT. No explosions yet. Same with the last one, and that one did not fly apart. Instead, it just wore out. As long as you dont go overboard and constantly run it at high RPMS, it will be fine. For a simple performance street engine, theres not much reason to build anything exotic.

If you have money, better heads and a good cam would make it run much better. Mine has 9.2:1 CR with trickflow heads and a single pattern 221/.465 106 LSA isky cam, and it runs quite well up to the redline. Its a shame they dont still just sell the shortblock, because for just a little bit more you could build a much better engine. Its a waste to buy a whole engine and toss the heads, valvetrain, and cam. If your going that route, you might consider just getting teh baseline version and save some money. AFAIK, the shortblock, most of the valvetrain, and heads are the same. The heads, though, are complete garbage, and ideally should go.

dimented24x7

iTrader: (2)

Heres a video that shows what the engine can do when its set up to make power out to 5500 RPM or so. The car still has 2.77's, so the acceleration isnt the best in 3rd as it falls out of the powerband, but other than that, its pretty good for a budget engine.

http://www.youtube.com/watch?v=3We7OO5pPCE

EvilCartman

iTrader: (1)

By the time it eats itself, you'll probably have another engine already. The rods are fine, the crank is fine. As long as you keep up on maintenance, it'll last a long while. I've been beating on my 350 for over 6 years now. Yes it's been balanced, yes it has some decent rods but I'm running a GM steel crank in a 2 bolt main block turning 7000-7300 rpm. Point is, quit worrying and pick out some parts that will work well together.

Atilla the Fun

Yeah, or you can take advice from an experienced professional engine builder such as myself.

86IROCracer89

yea its already been in the car for over a year so its too late to just buy the short block to save money. that and when i bought it i never thought i was gonna do to much to it, and it was a running budget block with more power then my 86's blown up 305 had to offer so i was happy..... then my cousin bought an LS1. so i saved up some cash for the hsr and everything to go with it and the cam, then i should have the heads for it by july.

as far as constantly revving it out, just an idea is that i would rev it out about once a day that i drive it, maby a couple more than that if im out with friends, as far as sustained high rpm's..... i live in the mountains, anything more than 100-110 for more than a couple seconds would ussually end up bad.

regal301

350/290 HP Tech Specs
Block Part Number:
10066034
Block Type:
Cast iron with 4-bolt main caps
Bore x stroke (in):
4.00 x 3.48
Camshaft duration (@.050 in):
222 degree intake / 222 degree exhaust
Camshaft lift (in):
.450 intake / .460 exhaust
Camshaft Part Number:
3896962
Camshaft type:
Hydraulic flat tappet
Compression ratio:
8.5:1
Connecting Rod Part Number:
10108688
Connecting rods Type:
Powdered metal steel
Crankshaft Part Number:
93426651
Crankshaft Type:
Nodular iron
Cylinder head Part Number:
93438648
Cylinder head Type:
Iron; 76 cc chambers
Displacement (cu in):
350
Engine Name:
350/290 HP:
Engine type:
Chevy small-block V-8
Ignition timing:
34 degree total BTDC
Maximum rpm:
5100
Piston Part Number:
12514101
Pistons Type:
Cast aluminum
Recommended fuel:
87 octane
Rocker arm ratio:
1.5:1
Rocker arms Part Number:
10089648
Rocker arms Type:
Stamped steel
Valve size (in):
1.94 intake / 1.50 exhaust

READ THE SPECS FROM GM BEFORE YOU OPEN YOUR MOUTH.

Maximum rpm:
5100


THE DUDE DOSENT WANT TO BLOW IT UP. AND I DONT CARE IF YOUR JESUS F' IN CHRIST,YOU DIDENT BUILD THAT MOTOR.............

THAT MOTOR WASENT BUILT WITH TOP SHELF PARTS.

regal301

for stock internals that is screaming.........

dimented24x7

iTrader: (2)

Thats the redline with respect to the power output for that configuration. For the shortblock, the max recommended RPM is listed as 5500 RPM from GM. These are similar to the vortec shortblocks, and GM limited those to 5600 RPM.

dimented24x7

iTrader: (2)

If he keeps the stock heads, it wont make it much past 5500 RPM or so, anyway, without getting pooped. My engine will happily rev past 5500 RPM with aftermarket heads + valvetrain, but with the use of a rev limiter, its not an issue.

regal301

i replied to his "i would like to rev it to 6,000 rpm" comment, along with the quote above..........

i hear a rod knock in the future.........................

and that queen song ........another one bites the dust.

regal301

Quote:
Originally Posted by regal301
what are your plans for this car..................if its a daily driver street car i would build it to stay UNDER 5,000 RPM.

the stress on that motor from repeatedly screaming it past 5k is not going to be worth any power you think your missing out on.

like i said before i got the" oh bull " comment,hes not missing out on anything above 5k.( even with a cam and intake)

dimented24x7

iTrader: (2)

In case you missed my earlier post, GM lists the max recommended RPM for the short block assembly as 5500 RPM. Does it mean that its bulletproof there? Probably not, but it their engine, and their recommendation.

With the stock heads, you probably wouldnt be missing out on anything above 5000 RPM. But with aftermarkets and a bigger cam that might go to 6K, the extra couple hundred RPM help, especially on shifting to the next gear.

Saabster

iTrader: (2)

Everywhere I've read the limit for a stock GM shortblock is 5500 rpms SAFELY. Yeah, you can push it further, but it's not really recommended much.

This isn't really a bad thing, with good flowing heads you won't need too much cam to make peak power by 5500. This means monster torque and decent fuel economy.

I'd recommend Trick Flow Super 23 heads. They have a smaller chamber at 62cc so they'll yield a more health compression ratio. If you're a bit crazy you can go for the Trick Flow 305 heads and have some serious compression.

86IROCracer89

yea i was looking for some smaller combustion chambers to bumb the comp and yea im thinking no more than 5500 at this point. i have a while to decide on the heads but even the cam hasnt been 100 percent chosen. i want to stay around the same duration but what do you guys think is a good lift for the rpms. i already planned on staying under 500, so shoot me a number.

Atilla the Fun

You want proof? I do have it.

Atilla the Fun

Chill. I've abused several of these, I know what they'll survive. I know first hand, and I know from my customers. GM isn't god. They always under rate everything. They're more interested in avoiding law suits. I'm more interested in helping enthusiasts, to protect my sterling reputation, so pipe down already.

Atilla the Fun

Are you wanting an off-the-shelf cam, or would you be willing to order something custom? Do you want to stay non-roller, or are you willing to convert?

86IROCracer89

just some good numbers, if have to special order it i could do that or if its something summit would have in stock that would be cool too. i was really just looking for another flat tappet to just stuff in there and go.

Atilla the Fun

In that case, I'm going to stick with the cam I posted up there at the beginning of this thread. It will pass an emissions sniffer, it will be great with your compression, it will make amazing mid-range torque, it will have a noticeable idle, but not rough, and it will like being shifted at 5500 rpm. It doesn't require anything special, either. If you're against always needing premium unleaded, I can list something else. This one will do fine with nearly any gearing, though it's best with 3.42:1, and it won't like 2.73:1.

86IROCracer89

yea i always run 93, and have 3.27's so not too bad but i may be in the market for a new rearend sometime soon because i think this ones going. at any rate ill look into that cam. as far as inspection.... my father's garage inspects my car and PA only has a visual emission inspection anyway so im not even close to being worried about passing emissions/inspection.

dimented24x7

iTrader: (2)

Are you opposed to changing the heads? A good cheap way to wake up that engine is with a set of vortec heads. For ~$800 or so, you can get the heads and intake. Theyre much better than what is on there now, and they will bring the compression up to ~9:1 with the standard felpro gasket. With a mild cam that has lift <.460 or so, these make really good power. With the addition of offset retainers and different springs, you can get more lift out of them. That, and the newer chamber works fine on regular 87. They only need around 32 degrees max timing at WOT, and are much more resistant to detonation than the original heads with the 76cc chambers.

86IROCracer89

as i said earlier i was looking at new heads but i just need to save up some money first. ive been looking at some cast aluminum non-vortec heads and think thats the route im going to go in seeing as how the HSR i have is the non vortec style. and yes i plan on smaller combustion chambers to bump up that measly 8.5/1 ratio i got going on.

Atilla the Fun

I know GM claims 8.5:1, but it's really 8.0:1 with steel-shim head gaskets, or 7.8:1 with GM composite head gaskets. Even Less with aftermarket composite head gaskets. So a 62cc head would put you close to 9.2:1, which is why I'm sticking with that cam. the 218/226 at 50 will give you strong power up to 5500, but the 262 at .006" will help trap what air it gets, keeping your dynamic compression ratio from being low.

Saabster

iTrader: (2)

So where is the discrepancy? Are the heads bigger the 76cc or are the piston dishes much larger than they claim? Or is it a bit of both? I'm curious because I was thinking of getting one of these short blocks should my 305 give up the ghost one day.

Also, try the TFS 305 heads. They have a 56cc chamber, it should make the compression more better.

Atilla the Fun

Here, do the math yourself: Swept volume of 716.74cc, deck volume of 5.15cc, gasket volume of 6.06cc, piston volume of 18.2cc, including the beveled outer edge, and head volume of 76cc. Add up everything but the swept, that's your burn volume. 105.41cc. Swept plus burn, that's total, then total divided by burn, that's 7.8:1.
This is with the GM 10105117 head gaskets. 4.100" bores, 0.028" compressed thickness.
yes, this engine is just $1,767, but for an extra $424 you can get the 12530282, which is 9.4:1 with the good Vortec heads, hyd. roller lifters, dogbones, spider, et cetera. And the 1-pc rear main seal. The cam is tame, but this is still the only GM crate engine that comes anywhere near being worth the asking price.

Atilla the Fun

Okay, have them milled to 51cc, which you should do for your 305 anyway, they'd put this engine at 10.24:1. Excellent.
But then you're still out $1500+ for the short-block, and that's dumb. You no longer have a warranty, and any local shop could do it way cheaper. Plus the TFS 175cc heads, at $1000, you're $2500 into your engine. What do you now have? A non-roller ZZ4. Dumb.
Converting it to roller adds another $250 for lifters and pushrods, and another $250 for a decent cam. At this point you're looking at under 400 horses for over $3000.
Does that sound good to you? I can make that number for half that price.

Saabster

iTrader: (2)

The piston dish volume was a mystery to me until now, I was back calculating to figure it out as I didn't see it stated anywhere.

I was thinking more about the #12556121 short block, which is a 1 piece rear and roller provisions, but it seems to have the 18cc dish pistons too. However, it's only $1200 and I could carry all the missing parts over from my 305.

Atilla the Fun

I'm not familiar with that one. I'll post again after I look it up.

Atilla the Fun

Okay, found it. Those pistons are somewhat better, they are not bevelled around the edges. That's a pretty sweet deal. Good find! With a 54cc head, a fel-pro steel shim, and assuming those pistons are 13cc as GM says they are, and assuming they're 0.025" below the deck as is nearly always the case with these things, your compression would be 10.512:1. That's great unless you're at sea level, in Cali, trying to get it smogged with a cam that has other than exactly 0 degrees of overlap at 50, no more, no less, which is possible. This combo would LOVE the GMPP HOT cam, and you'd be right at 400 HP.

Saabster

iTrader: (2)

Does it have the same 5500 rpm rev limits as everything else?

Atilla the Fun

Unlike the dang 7.8:1 versions, these use powdered metal rods, these are okay if you want to make the 1-2 upshift at 6000, which is right if you do use the GMPP HOT cam. No worries doing that forever. But don't hold the revs up there for any length of time. Other than a quick blast down the quarter mile, keeping it to 5500 is well-advised. Besides, with the TFS heads and the HOT cam, your HP will peak right around 5500 anyway. If you do go this route with a 700R-4, definitely hold first to 6000 when you want best acceleration.