steve350hp

hi been following this board awhile need your help looking for airflow #'s on 305 cylinder heads #14014416 ?

IROCaholic

I dont know all the numbers but I think they flow 195cfm @ .500 which is pretty good for a stock 305 head. I have them on my 350 with bigger valves and a small amount of work on them and I like them alot.

steve350hp

thank you IROCaholic looking at maybe using this head on 350 buildup. this head number is easy to find everybody says low performance.if they flow adout 195cfm they are not that bad

ME Leigh

From Kitch:

More 416 flow numbers
I've just finished reflowing my 416 heads with a 1.9" intake valve ( turned down manley 1.94" race flow valve).

Stock 1.84" valve in ported intake
Lift........CFM@ 28"
.05...........29.4
.10...........57.4
.15...........88.3
.20.........122.1
.25.........152.2
.30.........172.9
.35.........188.7
.40.........201.8
.45.........213.3
.50.........217.8
.55.........220.7

Modified 1.9" valve in ported intake
Lift.........CFM@ 28"
.05...........33.0.........+3.6
.10...........65.3.........+7.9
.15...........98.2.........+9.9
.20.........129.8.........+7.7
.25.........158.5.........+6.3
.30.........181.3.........+8.4
.35.........200.4.......+11.7
.40.........217.2.......+15.4
.45.........230.0.......+16.7
.50.........227.2.........+9.4
.55.........221.4.........+0.7

steve350hp

thanks ME LEIGH that will help alot you wouldnt happen to have the stock flow #'s ? i am looking to use heads unported.

ME Leigh

I don't have stock 416 flow #'s but i do have 081 #'s. THey should be very similar considering they are about the same head with center-bolt VC's

Flow chart for stock #14101081 305 head 87 91

Intake lift (in) Flow (cfm) Exhaust lift (in) Flow (cfm) Ratio E/I flow (%)
0.050 31 0.050 15 49
0.100 63 0.100 37 58
0.150 92 0.150 61 67
0.200 116 0.200 78 68
0.250 134 0.250 92 69
0.300 157 0.300 101 64
0.350 170 0.350 105 62
0.400 182 0.400 107 59
0.450 189 0.450 109 58
0.500 195 0.500 110 56

steve350hp

thank you ME LEIGH

IROCaholic

Wow so are you saying that on that first set of numbers you only did work on the intake ports and left the combustion chambers untouched? Those are really nice numbers especially with the stock valves. Oh and steve350hp your really going to want to at least get 1.94 and 1.6 valves installed on these heads if your going to use them on a 350 the stock valves are going to rob you of a pretty good amount of power.Good Luck.

Sitting Bull

Those cheap 305 heads make for a darned good home port and polish project for your average smallblock, eh?

IROCaholic

It defenetly makes me think about taking mine off and doing a little bit of work on the intake and exhaust ports later down the road. Hey how much flow do you think these heads pick up with just the addition of the bigger valves just out of curiosity? Would you say about 10 cfm's or so?

steve350hp

thanks for the info IROCaholic just curious how close the flow #'s were to a set of 186 heads that i have now looking for cheap set of head readily available was thinking of having 1.94 intakes put in heads have to be stock ports no port work or ginding marks also we have to run a restrictor plate with 15/16 holes & a holley 4412 500 cfm carb.the number for stock 416 if are at 195cfm @ .550 lift would not be that bad ?

chevycamaro91

iTrader: (1)

im retarded cuz im prolly looking rite at it. but whats the highest durantion stock 081 heads will allow?

mw66nova

iTrader: (13)

NHRA Stock and Superstock guys run HUGE duration cams (stock lift is what they are limited to) on stock runner 416 and 081 heads with great results. i'm talking like 250+ @ .050 on a 106 or SHORTER lsa! rich aman is running them in his 86 sportcoupe (rich is the H/Stock record holder) with some ridiculous cam specs and has been 10.98 @ 120mph! stock 9.5:1c/r, approved pistons/rods/crank, no more than .060 over 305 block, stock 416 heads with stock size valves, though you can run any angles on the back of the valve you want.

Randy82WS7

good thread

wow you opted ot leave the 1.84 valves in them ?

really ?

interesting

i always have stock 1.94's and z-28 springs put on them since its cheap to have done

good thead

is there a way to compare the numbers from these heads to any others, just to get an idea of how good they flow ?

or ?

just curious

the numbers dont really mean much if you dont know how well other heads flow

you know,

thanks

ShiftyCapone

iTrader: (7)

Here is an excellent thread on 3rd gen head flow data.



TBI and TPI head flow data

New2Chevy

iTrader: (11)

Wow I was reading a pretty old thread. Good information, though.

Saabster

iTrader: (2)

I've always been perplexed by the 416/081 heads, given how crappy the exhaust flow is.

Camarillo

So I am curious about the head numbers... here is why, looking through the Classic Industries catalog the replacement engine page lists #081, 187 for the heads, on several years (3rd gen) for both TPI and TBI. Are LO3 heads 081 or 187, or are both numbers apart of the same head? Didnt want to start a new thread since this one involves my questionable numbers.

Atilla the Fun

187 are swirl port, 081 are worth having.

Atilla the Fun

That's can't be right. My testing on the SuperFlow 1020 has the stock 081 exhaust ports with stock valves cleaned up reaching 145 cfm even without a length of header pipe.
On the intake side of the 416 heads, with stock valves cleaned up, the number averaged 185 cfm maximum.