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305 head flow possibilities?

General engine tech -- Drag Racing to Circle Track

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rfoll
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Re: 305 head flow possibilities?

Post by rfoll » Wed Oct 16, 2019 11:04 am

1.56" ch Speed Pro flat tops for a 305 can be had for under $150.
So much to do, so little time...

Bill Chase
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Re: 305 head flow possibilities?

Post by Bill Chase » Sun Oct 20, 2019 7:40 am

113 corvette castings are cheap. Easier to port.

gmrocket
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Re: 305 head flow possibilities?

Post by gmrocket » Sun Oct 20, 2019 2:47 pm

Bill Chase wrote:
Sun Oct 20, 2019 7:40 am
113 corvette castings are cheap. Easier to port.
What's that?

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Re: 305 head flow possibilities?

Post by Carnut1 » Sun Oct 20, 2019 3:27 pm

gmrocket wrote:
Sun Oct 20, 2019 2:47 pm
Bill Chase wrote:
Sun Oct 20, 2019 7:40 am
113 corvette castings are cheap. Easier to port.
What's that?
2nd design aluminum Corvette head. 1.94"/ 1.5". With 2.0" / 1.55" valves and some porting they go about 260/185 cfm.
Servedio Cylinder Head Development
631-816-4911
9:00am - 9:00pm EST

rfoll
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Re: 305 head flow possibilities?

Post by rfoll » Sun Oct 20, 2019 5:38 pm

Are all of those Corvette aluminum heads angle plug? It could be a problem with some exhaust manifolds and headers.
So much to do, so little time...

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Re: 305 head flow possibilities?

Post by PRH » Sun Oct 20, 2019 6:31 pm

I put together a low buck 305 about 20 years ago.
Zero deck with that tops, RPM intake, headers, 650dp carb, Elgin 920 cam.......9.6cr as I recall.
Heads started out as 1.72’s...... 434 casting number maybe?? Looked like 882’s, but for a 305.
I put 1.84’s in, nice valve job, blended bowls.
I don’t remember at all what they flowed.

Made 330hp, and hung on pretty good to about 6500.
Somewhat handy with a die grinder.

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Re: 305 head flow possibilities?

Post by jeff swisher » Thu Oct 24, 2019 3:56 pm

I ran the little 1.72- 1.50 305 heads on a 350" In a 3300lb 78 nova.
The heads were off the 78 Nova 305 engine.
Built this car for a buddy. He said he was getting some AFR heads but for now lets work the bugs out.

I bowl ported the small valve heads and radiused backcut the valves.
Smoothed the chambers and removed all sharp edges in the combustion space.

280H comp magnum flat tappet with Z28 springs and 1.5 rockers.
That cam is 230@ .050 and .480" lift on a 110 LSA.
.044 piston to head clearance (includes gasket) and TR1YX 12" tall dual 4 tunnel-ram and 2 edelbrock 600 carbs.
Pertronix point conversion Ford coil and 91 octane fuel.

TH 350 with a converter that stalled to 2200 rpm. 4.57 gears in a 9" under the back.

It went 12.51 at 111 MPH Not bad for small valve head junk.
Shift point was 6700 RPM.

He decided against AFR heads after that. and got some of the HO 305 heads the 601 castings and 1.94-1.50 valves went into them.
Stepped up the cam to the old 292H.
Drank a lot more 91 octane fuel but went 11.94 at 115 MPH. Yes those 601 got ported.

I say keep the small valve and run it.. you will be down about 400 RPM at the peak vs a 1.84 valve that has .89% or a bit more valve to bowl diameter.
At least in my testing.

And when I went to 1.94 valve in the 601 head it lost power..I did unshroud the stock chamber in the 601 head for the 1.84 valve and a tick more for the 1.94 but not nearly enough near the spark plug area of the chamber.
I hooked it out even more for the 1.94 and chamber ended just about 62cc.
Stock I measured the 601 at 53.5 and I could get by with 57-58cc with the 1.84 valves.
The 450 head with small valve did not need any unshrouding.

gmrocket
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Re: 305 head flow possibilities?

Post by gmrocket » Thu Oct 24, 2019 4:22 pm

jeff swisher wrote:
Thu Oct 24, 2019 3:56 pm
I ran the little 1.72- 1.50 305 heads on a 350" In a 3300lb 78 nova.
The heads were off the 78 Nova 305 engine.
Built this car for a buddy. He said he was getting some AFR heads but for now lets work the bugs out.

I bowl ported the small valve heads and radiused backcut the valves.
Smoothed the chambers and removed all sharp edges in the combustion space.

280H comp magnum flat tappet with Z28 springs and 1.5 rockers.
That cam is 230@ .050 and .480" lift on a 110 LSA.
.044 piston to head clearance (includes gasket) and TR1YX 12" tall dual 4 tunnel-ram and 2 edelbrock 600 carbs.
Pertronix point conversion Ford coil and 91 octane fuel.

TH 350 with a converter that stalled to 2200 rpm. 4.57 gears in a 9" under the back.

It went 12.51 at 111 MPH Not bad for small valve head junk.
Shift point was 6700 RPM.

He decided against AFR heads after that. and got some of the HO 305 heads the 601 castings and 1.94-1.50 valves went into them.
Stepped up the cam to the old 292H.
Drank a lot more 91 octane fuel but went 11.94 at 115 MPH. Yes those 601 got ported.

I say keep the small valve and run it.. you will be down about 400 RPM at the peak vs a 1.84 valve that has .89% or a bit more valve to bowl diameter.
At least in my testing.

And when I went to 1.94 valve in the 601 head it lost power..I did unshroud the stock chamber in the 601 head for the 1.84 valve and a tick more for the 1.94 but not nearly enough near the spark plug area of the chamber.
I hooked it out even more for the 1.94 and chamber ended just about 62cc.
Stock I measured the 601 at 53.5 and I could get by with 57-58cc with the 1.84 valves.
The 450 head with small valve did not need any unshrouding.
88FBIRD is wetting his pants over that 😜

gmrocket
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Re: 305 head flow possibilities?

Post by gmrocket » Thu Oct 24, 2019 4:24 pm

Does anyone have stock flowz #'s for the 1.72" and 1.84" 305 heads?

Want to know what I'm up against

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Re: 305 head flow possibilities?

Post by maxc » Thu Oct 24, 2019 5:20 pm


pdq67
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Re: 305 head flow possibilities?

Post by pdq67 » Thu Oct 24, 2019 5:45 pm

Please use a set of 305HO, -601 heads, but check the cc on them because they vary from down around 53 cc's to 58-60 cc's!

They have a true double quench design, 1.84"/1.50" valves and 160 cc intake ports!

On a small engine, use either Feolpro's 1094 015" head gaskets or MrG .020" thick shims!

Just douvble check your CR here!!

psq67

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Re: 305 head flow possibilities?

Post by jeff swisher » Thu Oct 24, 2019 6:00 pm

That is a great link I have seen it and used it a few times.
I concentrate on shape more than I do on flow numbers.
Flow numbers are fun to see just like HP numbers but it is not the end all.

You may not have seen this.
My 1957 4door 210 Chevy with trailer hitch that pulls my 20 foot Pontoon across the state.
Vs my buddies over 550 wheel Hp 2015 Coyote mustang..Yea neither car is stock.

I have my 350" with flat tops. Ported 601 heads with the stock 1.84-1.50 GM valves Beehive springs 313 spring rate and 280H magnum flat tappet hydraulic with crower cam saver lifters. Stock rockers and pushrods and stock rocker studs and balls.
Th 350 and 4.56 gears in a 9" 3650 race weight on my 4 door. Tunnel-ram with 2 stock jetted 600 edelbrocks. 14.5 idle and part throttle AFR 12.8 wide open AFR.
Single point distributor from autozone with lighter springs.
91 octane fuel.
I told him for 3 weeks i would kill him out of the hole and he may not be able to catch me by the end of the 1/4 mile.

He has a 6 speed stick and 3.73 gears.
My car is more than 250 HP less at the wheels..But i ain't skeered of some stick shift Mustang.
Bad deal on the burnout I did..seemed my distributor was not tight enough and my timing dialed back to 28 total Lost my top end and some initial power.
Still a win. TNT Friday grudge night and I got 1 more pass and dialed in the correct 38 total timing but it wheel hopped because i did not install my leaf spring clamps so i had to back out and went slower but with more MPH.
You can make the car right and be down a bit on power vs your opponent and still whoop him or her.


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Re: 305 head flow possibilities?

Post by F-BIRD'88 » Thu Oct 24, 2019 9:44 pm

gmrocket wrote:
Thu Oct 24, 2019 4:22 pm
jeff swisher wrote:
Thu Oct 24, 2019 3:56 pm
I ran the little 1.72- 1.50 305 heads on a 350" In a 3300lb 78 nova.
The heads were off the 78 Nova 305 engine.
Built this car for a buddy. He said he was getting some AFR heads but for now lets work the bugs out.

I bowl ported the small valve heads and radiused backcut the valves.
Smoothed the chambers and removed all sharp edges in the combustion space.

280H comp magnum flat tappet with Z28 springs and 1.5 rockers.
That cam is 230@ .050 and .480" lift on a 110 LSA.
.044 piston to head clearance (includes gasket) and TR1YX 12" tall dual 4 tunnel-ram and 2 edelbrock 600 carbs.
Pertronix point conversion Ford coil and 91 octane fuel.

TH 350 with a converter that stalled to 2200 rpm. 4.57 gears in a 9" under the back.

It went 12.51 at 111 MPH Not bad for small valve head junk.
Shift point was 6700 RPM.

He decided against AFR heads after that. and got some of the HO 305 heads the 601 castings and 1.94-1.50 valves went into them.
Stepped up the cam to the old 292H.
Drank a lot more 91 octane fuel but went 11.94 at 115 MPH. Yes those 601 got ported.

I say keep the small valve and run it.. you will be down about 400 RPM at the peak vs a 1.84 valve that has .89% or a bit more valve to bowl diameter.
At least in my testing.

And when I went to 1.94 valve in the 601 head it lost power..I did unshroud the stock chamber in the 601 head for the 1.84 valve and a tick more for the 1.94 but not nearly enough near the spark plug area of the chamber.
I hooked it out even more for the 1.94 and chamber ended just about 62cc.
Stock I measured the 601 at 53.5 and I could get by with 57-58cc with the 1.84 valves.
The 450 head with small valve did not need any unshrouding.
88FBIRD is wetting his pants over that 😜
Sorry was busy with work stuff. Up Jeff does good with his low buck combos.. 305 heads etc. The tunnel ram makes great torque right where you need it. It's a factor.
Don't expect big thing G's from the 1.72" valve version.
They are pretty modest.
Lots of better start points.

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Re: 305 head flow possibilities?

Post by randy331 » Thu Oct 24, 2019 10:38 pm

Throw those 305 heads in the junk pile and spend your time on something better.
Or sell them to one of those on here posting how good they are.

My son wanted to go down that road and I talked him into buying some rhs vortecs. (me being willing to port the rhs heads helped his decision a lot. LOL) I fitted them up with some left over valves/springs etc and ported them for him. Now he has a set of nice thick casting nicely ported heads that will make way more power than any factory head and won't crack.

Randy

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Re: 305 head flow possibilities?

Post by vortecpro » Thu Oct 24, 2019 11:11 pm

305 stocker.jpg
econo racer wrote:
Mon Oct 14, 2019 7:27 am
With all these new ways of getting lots more power on the 305. What cam and intake should work with the 305 engine to make it run 12.20.?

Its worth mentioning NHRA 305 stockers have run at least 10.60s with 1.840/1.50 valves, factory intakes and Q-Jets, with .410 lift cams.[attachment
You do not have the required permissions to view the files attached to this post.
Racing a NA NHRA stocker should be mandatory before any posting.

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