I can't find the answers i want so if anyone could knock a question or two of my list id appreciate it.

1) i have a 350 from an early 70's truck, im under the assumption its a 9:1 comp. engine with 70cc heads? possibly more cc's, as the camaros and chevelles had 64cc heads which gave them 11:1 comp. correct me if im wrong.

2) based on the above 1985 lg4 305 heads at 58cc? installed on the same 350 would net how much? i know it will be more then 11 i just want to know, guesses are welcome

3) oil pan and pump and pick up - i need new as there is no existing, engine will be the 350 with afrs and comp solid cam/lifters 10:1, 2000rpm-7000rpm. i was expecting 200 bucks for the oiling system but i could spend more. they have to clear stock k member and hooker long tubes, they will eventually go on to a new short block (383) this winter.

suggestions please

/thanks.

 

a Melling stock replacement oil pump and pick up will work great.

a moroso 6qt oil pan will work great or i used a milodon replacement on mine...actually....i have it at the house, it only has about 150miles on it or so...i'd take $60 plus shipping for it...it's for the pre-79 block with the drivers side dipstick

as far as your c/r questions go...you'll need to know quench depth and piston cc to come up with any kind of real answer. normally, they were in the 8.5:1 c/r range back in the day...based on that and going from a 76cc head (what came on it stock) to a 58cc head with an .041" gasket, compression would be in the ~10.2:1 compression ratio range...though these are hypothetical numbers based of a piston with a 6.7cc volume (flattop four valve reliefs)

 

thanks for the offer and info. for now ill pass on the pan.

and as far as the comp ratio go the short block does have the 4 valve relief pistons and they also have a 30 marked on them. I would take it they are .030 over pistons?

and as far as the heads go, i remember reading awhile ago people running 305 heads on their 350s, i was wondering if i could do that to bump up the comp ratio for a few more horsepower until i get the afrs. in other words will have enough piston valve clearance???

thanks for the help

 

the geometery of the valve is unchanged regardless of the combustion chamber size, so as long as the cam doesn't have some crazy lift on it, then it'll probably be fine. it is a decent way to boost compression ratio though once you put your 64cc AFR's on it, the c/r will drop again. 030 stamped on the piston means it's been bored .030" over. are there any other markings on the pistons? it wouldn't be a bad idea to identify exactly what you have in there. cause alot of stock style replacement pistons stick the piston .020" further in the hole to compensate for decking the block (if it needs if, if not, you have a piston that is .020" further in the hole...this can mess with quench)

 

ok so did a little research

the pistons are .030 over and there are no other markings on them they look flush with the deck.

the block is a 3970010 casting which agrees with the story of a 350 out of a 71 suburban.

the heads however are 462624 which when i checked says 1975-1986, 76cc 350/400 and they were available with 3 different types of valve setups.

i still can't find out the comp ratio, however a friend of mine still stands that there were 2 main types of 350's in the early 70's; 76cc which neted 9:1 and 64cc which neted 11:1. On this fact 305 heads or 58 cc would put me in 12's:1 and to much for 93 octane which is as far as im willing to go.

however if your right and its 8.5:1 58cc would yeild high 10's:1 comp ratio.

/opinions and comments welcome.
/another month til i have the cash for the afr's and a cam.

 

your friend is wrong. 76cc should be around 8.5:1, 64cc around 9.X:1, and 58cc 10.X:1 or so.

 

just what i wanted to hear. and i know its an estimate but your 9.X:1 and your 10.X:1 are in what range .0-.5 or .5-.9?

thanks.

 

i'm guessing 9.5:1 and 10.5:1 but it's all a huge guess. are the pistons 4 valve reliefs, etc etc anything could change it.

 

ok, if the pistons are flush with the deck, that means the block has been zero decked. your c/r is going to be up a bit more. you'll be running into the upper 10:1 range, like 10.7:1 or more....with iron heads and a carb....that's gonna be a bit much without some kind of fuel additive.

have fun.

 

yeah they have 4 valve reliefs.

and back to the oil pan question, a milidon stock replacement would be ok? with a stock replacement pump? The 305's oil pressure now drops to low single digits under hard braking now, something id rather not have especially if im buying new. Could someone recomend me something a bit better then stock maybe with a baffle; like a street / strip pan that would clear the hooker long tubes. Im not asking for a 10 quart, kicked out, $400 pan with 2 trap doors, a millions baffles and crank scrapers; just something to keep the pressure consistant through 0-7000 rpm and under hard braking. With the 64cc afrs my comp ratio is looking like 9.7:1 range then.

thanks for the info everyone.

 

low single digits when braking? check your oil level dumby...it's low and running away from the pickup.

i'm running a Melling high volume pump, though if i had the extra $15 when i rebuilt this motor, i'd have put a standard pump in it (worth a few extra horsies) cause it takes less to turn the standard volume pump than the high volume.

as far as the oil pan, i've had a few high hp motors in the car and that milodon pan worked great. i spun that motor to 6200rpms without any issues.

 

oil was never low not in the 2 years i drove the old 85, checked everytime i filled up with gas. EVERYTIME. (i was in high school, nothing else to do)

You don't think the high volume is worth it? Extra protection vs a few horsepower? I don't know thats why im asking.

any other opinions?

 

my machinist said it's not necessary to have a high volume pump...i bought mine several years ago when i didn't know any better and it works great. it's up to you at this point. if your having oil pressure issues now and it's not low oil...sounds like you may have some spun main bearings or something...there is something a miss there for sure. whenever rebuilding the motor, either check out the current oil pump and rebuild it if necessary, or spend some money and buy a new one.

if having 60psi on start up at idle makes you feel better than 45psi, then cool...though i don't know that it is necessary as long as the pump is in good working condition...

 

my hard braking issues and low oil pressure were on the 305 so ill leave my problems with that and move on to the 350 with a new pump.

And 45 seems fine to me so i think im staying with the standard volume. What would be a reason to use a high volume and is there a difference between standard/high volume and standard/high pressure oil pumps?

thanks

 

the difference is just that, one gives more volume and one gives more pressure. honestly, i've heard nothing to support mandating a high volume/pressure pump in a performance application. it's just a gimic. and it's actually possible to have too much pressure, where the oil goes through the motor too fast and doesn't give proper lubrication becuase it's flying past the bearings.

 

asked my machinist's opinion today...said the same thing.

good information.

 

think i'd steer you wrong? lol...

 

I don't know if this will help or not, but i'm running the same 3970010 block zero decked .30 over hyperutectic flat top 4 reliefs pistons iron heads 2.02\1.60 68.3cc chambers 0.41 crushed head gaskets and i'm pulling 10:4-1 comp. i was able to build it up to 497horse. not too bad for a small block. but as far as fuel gos i had to take 117octane mixed in1/2 with 91 to get rid of the fuel ping. hope this helps

p.s if it is built right you should be able to use a stock replacment meeling pump and get your engine the oil it needs, thats what i'm running and it carries 60 psi always. in my opinion all a high volume pump is good for is blowing gaskets.in less its a straight out drag motor.

 

mw66nova - thought never crossed my mind

more opinions / stories the better

and pontiacmo89 that does help what kind of heads were they?

And there is no way im shelling out the bux for c16 or even c12. 3.50 a gal for 93 is plenty expensive as it is with out going to 12-15 bux a gal.

 

they are 71 vette heads,they started out at 76ccs, after angle cutting, hardened seats and swirl polished ss valves they cc'd out to 68.3cc's. before i started them everyone i talked to told me that a stock 76cc head couldn't be taken down past 70cc, needless to say i shut them up.

about the gas where i live 93 is 2.76 a gallon and 117 is from my race shop it gos for 5.00 a gallon.

 

another thing i wanted to mention is that around here we don't run 93 octane, we run 91 believe it or not 91 is much cleaner than 93. after taking down motors that ran 93 and ones that ran 91 we have found that all the motors running 93 had carbon deposits an the pistons and valves like crazy, even after only 3 races on them, the 91's are almost always spotless. we think it's because of the fuel base. who really nos these things anyways

 

91 is cleaner? can anyone else support that? never heard that before...something else to ask my machinist lol.

anyway i work at a raceshop and 5bux a gallon is a steal. what brand?
We charge 50-70 bux for a 5gallon keg of the stuff. ranging from c12 to n02 fuel.

nice work on the heads by the way...i take it you did it yourself.
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grr.

 

crap.