Does anyone know what the exact compression would be with a 350 block bored .030, stock crank/rods, stock pistons with casting #1402 2601 54cc 80-84 305 heads? Is there a formula for this? my engine pings with anything less than 91 octane so im guessing the compression is fairly high. Also could they be made to flow?? (port/polish) if not i think vortecs might be in order. All of the valvetrain is brand new, the guy who had it before siad it has a lt1 vette cam too, but i would think that the engine is dying for air...

You'd have to know what pistons they are, "stock" doesn't mean anything, especially when the engine has been bored.

Try this for a calculator, though. http://www.csgnetwork.com/compcalc.html

Those are 53cc cylinder heads. They are the BEST flowing STOCK 305 heads made prior to the 059 vortecs, ported they flow pretty darn good while retaining a small runner. I ran them on a 12cc dished piston 355, at 10.5:1 compression with NO detonation. They will not like more than about 30* of total advance, but that is NOT limiting ANYTHING.

LT1 cam doesn't mean much as there are MANY LT1/LT-1 cams.

the calculator estimated about 10:1 or 10.00598909790862:1 lol, so i know its basically around there unless the pistons were changed in the last year. What would be a good cam for my engine? i want to do a complete rebuild within the next month keeping the car streetable. If these heads are capable of performing well ill port/polish the exhaust ports and get some bigger valves and a three angle valve job. any suggestions on pistons? or is it worth it to keep the heads?

In the calc with 12cc pistons its 10.9:1 compression..

12cc dish, not 12cc dome.
I like this calc
http://kb-silvolite.com/calc.php?action=comp
Pretty straightforward.

I agree with Fast355, do some port work, a valve job, maybe upgrade the valves and you're good to go. Are you in Red Deer? I forget... You're at altitude though, so you're a little better off with respect to detonation. If you have steep gears (I've never heard of 3.83 gears, 3.73?) then you can afford to cam it up, especially with a stickshift and 10:1 CR. I'd HIGHLY recommend the xe268 (not a plug, but I just pulled a useable one out of my car this week if you're interested) or the xe274h, or something of that size.

Not to thread jack, but how much difference does altitude make? Im near edmonton and have flattops in the 350 I just bought. Its about 10.5:1

No difference at all to static compression.

It mildly effects dynamic compression. I don't have a calculator handy (at work we use that for industrial engines, but it wouldn't be helpful to you). Basically with the less air (due to altitude) you can jet it leaner, (to become stoich). Think of the air pressure basically. When you go from 14.7psi at sea level to ... 12.x at 4000' or so, then you're losing basically... 20% of your air pressure? 20% less cylinder pressure is the punchline.

Yes im in red deer, Our altitude is only 900ft. The guy who i got the car from was an idiot and he siad the gears are 3.83 and i asked him well ive never heard of 3.83 do you mean 3.73? "No man 3.83" then he also siad i had a T6 transmission witch i don'tand ive never heard of so basically I really dont know much about the car, and he also stated that it has a brand new clutch but my car isnt even drivable right now becuase of it... How much you want for that cam sonix? and what are the specs?

No, I guarantee you Red Deer isn't at 900'. It's pretty close to 2500'. There's a lot of natural gas burning industrial engines there

Yea, g0d knows what gears you have then. Pop the cover and inspect it, then add fresh fluid. If 41:11 is stamped on the ring gear, then it's 3.73.
He might have put in the clutch wrong, put the throwout bearing on the fork wrong, that's common.

It's the Compxe268H, right here;
http://store.summitracing.com/partde...2&autoview=sku

It's one of the more common cams used in a 350. Lets see, I paid $135 for it, and $80 for lifters. I've used it for about 1000kms. No visible wear, but it is broken in, which is nice, because you wouldn't have to worry about breaking it in, and screwing it up. (been there, got the shirt...)

$100 sound fair?
I've meticulously arranged the lifters to go back on the right lobes.
While i'm hawking my stuff, I also have some 1.6 roller tip rockers, non-SA, stamped steel ones. I was using them with the cam as well, worked pretty good.

so $100 for the cam and lifters? how much for the rollers? Sorry i read it as 905 feet but its 2600 haha. I guess ill be making a trip to calgary soon DO you have a clutch or rad for sale by chance??

Yea, 900m sounds about right
Yep, $100 for both. I think that's about right. The way I see it, used auto parts lose 50% of their value as soon as they're installed.

Rollers? You mean the rockers? Uhh, lets see, they were $100 from summit... $50 sound fair? They'd probably just collect dust on me until I find a use for them, which would be a ways down the line.

haha, I have a stock clutch if you want that, would give me an excuse to upgrade. I replaced the friction disc last year because I thought it was trashed (it wasn't, but now it's new). So is the TO bearing. That clutch held up strong enough to blow apart my rear axle, so I give more credit to stock clutches than most people do....
But I want to keep my rad

For sure, make a trip down here, bring a q-jet if you want some help rebuilding it, and some hootch!

PM me for details if you're serious.

I had those 601s, with a small clean-up shave, on my flat top 350 and it worked out to something like 11.25:1 - took awhile to get the tune just right to where it wouldn't ping, but that thing pulled HARD once I got it right!! There was so much mid range torque with those heads and my XE274 cam, it was unbeleiveable. Only mods to the heads were 1.94/1.60 valves (and screw-in studs, guideplates, and cut for .550 lift, but that doesn't really affect how they perform.)

Compression ratio only gives you a rough idea on what octane fuel to use. There's only a couple of 305 head castings that can flow enough air for a mildly stock 350. Bigger engines need more air. You can go plunk some 265 heads on a 350 to build up the compression ratio but they'll restrict the engine so much it will run like ****.

Racing in Calgary you can normally see race days with a density altitude hovering around 5000 feet so you'll lose even more power.

There's lots of factors for tuning at altitude. An engine doesn't need as much octane as it would at lower elevations. Because there's less air to burn, less fuel is needed (leaner jetting). Timing can be advanced more.

I HAVE A COMPLETELEY STOCK #!$##%$%%$@#$% $@!#$ !@$!@#!@ 305!!!!!!!!!!!!!!!!!!!!!!!! The f*g i baught my car off lied to me and siad it was a 3970010 block but NOPE its a 14010203, 80-85, 305 block, But i dont understand becuase this car hauls *ss and is faster than the 350's i have had in the past i feel like calling the guy right now but... i realize its my fault. somebody slap me I can't beleive its a 305 im literally amazed any 305 ive driven in the past was very slow but this one is pretty fast, maybe mortec made a mistake?? at first i wrote down the # as 44010203 but the only thing close was 14010203 so i figured i just read it wrong ill check again...

hahahaha, sounds pretty typical.
But with 601 heads stock it might be a truck 305 motor. Well at least you know it won't have an LT1 vette cam in it.
Huh, then you don't know if it's been bored .030" either eh? Ouch. Are you tearing it down now?

ya it sux.... I'm just gunna keep it in the car and do my body work find a 350 block and build an engine over the summer/winter then drop it in next year. I'll still get those parts from you though!

14010203 is DEFINATELY a 305 block and potentially a 4-bolt main block. Mine came with 601 heads too. The block, if it is still stock, should have flattop pistons, a steel shim style head gasket, and a "929" 350 camshaft. They made around 190 HP stock, in the Truck, so there is no surprise that it could walk a 350, mine would run with stock TBI 350 trucks in a VAN.



Stock Flattops in the Block

Seriously Fast355?? Wow, that's actually not bad then. 190HP 305 is a HOT 305. That's basically one of the best 305 shortblocks then. Nice high CR and good heads. The 929 is a notoriously lazy small cam though.

If you're still interested in these parts i'd highly recommend you throw them into the 305 and leave that engine until it dies. Tell everyone it's a 350, nobody but you will ever know the difference. If the shortblock ever dies, you can always just replace the shortblock. ie keep the heads and cam. It'll still be a fun ride.

Buy some new 1.25" high perf springs and install this stuff. You'll be LAUGHING.

My lighty tuned TBI truck (94 Z71) was very slow, good low end trq but no power after that.. When i first got my car i was un-sure if it was a 305 becuase all the paper work the guy gave me siad nothing about a 350 but all my freinds assured me it was a 350 and were comparing it to one of my freinds 340hp 350 3rd gens. I guess the 305 is not so bad after all depending on induction. i still wanna 350

They were nothing to sneeze at in the compression department (210 psi cranking compression), GM started putting a knock sensor and an ESC system on them in 1981, but used a standard mechanical M4ME Rochester Q-Jet. The distributor had a vacuum advance, centrifical advance, and the ESC controller as well. The 929 is still hotter than the 817 or 155 that is known as the peanut cam. The 929 cam is 194/203 @ .050, .390/.410 to the Peanuts 179/194 @ .050, .350/.385. With Doug Thorley Tri-Y headers, 2 1/2" duals, and a 350 TBI setup on top of my engine, it made 191 RWHP @ 4,600 rpm and 274 ft/lbs @ 2,900. I put a mild 204/214 @ .050, .423/.442" RV cam in it and it came alive to 223 RWHP @ 4,800 and made 282 RWTQ @ 3,000.

Ya thats the funny thing, it already is fairly fast and fun, im shocked. I checked around the engine alot today and came to the conclusion that the short end is completely stock. The gaskets are all old and cracking but the guy siad it has a new cam as of last november... I'll throw your stuff in and get springs and see what this thing will do.. this engine right now really feels like a mild 350 even with a badley tuned carb in need of rebuild, Leaky exhuast manifold, Hillbilly rebuild (who knows how good that is), the only thing this car has is a k&N and 3" duals w/stock mani's. Did the 84 305's comes with blue paint??

My 1983 Van engine was Black OVER Blue. When the engine got some miles on it the black paint started flaking off to reveal the blue paint under it.

what is the internet adress to identifi "stock"sbc cams??? cuz i have an old cam in my garage and am just curious what it could be it's a "peanut" cam but i would like to know! all i can read on the cam is 1529 ,d11,18 near at the cam journals!

thanks !!!

Didn't alot of the truck/van 305s that had the 601 heads have higher compression (9.5:1ish) and the L69 '5.0 HO' cam?

If thats true, then you're off to a pretty good start for a 305. The 601 heads make pretty decent factory performance heads, and the L69 cam is pretty healthy. I had an L69 in my Camaro when I got it, and it was noticeably better than any of the late '70s Camaros I drove with the stock 350s.

Shoot, I keep forgetting. Are you still coming by on sunday creepingdeath to rebuild the q-jet and buy my cam/lifters/rockers?
Shoot me an email or PM to confirm, I haven't heard anything from you so if you're not coming i'll plan something else for the day. (and if you are, let me know when you think you'll be there so I can fire up the propane heater and get it toasty warm in the garage)