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  #16 (permalink)  
Old 08-06-2012, 05:32 PM
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305 heads on 350 short block, snap crakale pop

I built one once, the plan was a high efficiency 350 in my Blazer.
My first mistake was putting it in a 4500 pound vehicle.
My second was running it hard before i had the timing dialed in.
I had a roller cam setup, i used the Chevy 4 banger (shorty) roller lifters and Ford 351 push rods, a LT-1 cam, ported heads. ground and filed the valley to make the lifers fit, modified the lifter alignment bars, used d-dish GM pistons, compression was 10 to 1, i spent hours building this thing.
She ran pretty dare good, pretty peppy. i was merging on to the hi-way one day and liad into the throttle pretty hard, she pinged real hard and that was the end of it, i cracked both heads through the seats, when i got home she was steaming out the pipes like a choo choo train. that motor today is a 357 vortec with comp high energy cam with 9.8 to 1 compression. Would i ever build another one? nope...save up your denaries, new far supirior heads are so cheap now there like they woulda been next to free 15 years ago.

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  #17 (permalink)  
Old 09-11-2012, 06:03 PM
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So i followed every friggen post you have on porting the 416 heads lol, I have likely around 40+ hours in the friggen things..! I dropped them off yesterday at my machine shop and he called me back quickly. Turns out he is an older hotrod guy and loves these heads, he has been porting them and using them for years and absolutely loved the work I put into them and thinks they will work really well! He says they already had new bronze guides installed so he offered to install 194's at no additional charge as they hadntonbe re- seated anyways due to a couple slips with the die grinder. They are getting hot tanked, new valves, new seals, minor de- shouding due to the bigger valves, and assembled with my comp springs and appropriate shims.....out the door for 300$.....seems fair to me? I'm wondering, if anyone actually read this novel, if they could sim this combo to give me a rough idea of what to expect HP wise?
Heavily worked 416 heads
Perfomer intake port matched to 1205
1" Carb spacer
350 with flat tops using shim head gasket
Lunati bare bones cam pn# 10001k.
Duration 280/290, Lift .443/.465,*
Shorty headers
750 quad on top.
Thanks!
And p.s thanks a million f- bird for all your posts lol.
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  #18 (permalink)  
Old 09-12-2012, 05:38 AM
How fast is fast enough?
 
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Quote:
Originally Posted by 66GMC View Post
If you're planning to do 75 to 85 mph on the highway ... don't do it near Spruce Grove, Alberta. Right Harry? (Inside joke)

OK, seriously now ...
IMO Cylinder heads and camshaft selection won't have a dramatic effect on your car's ability to drive at consistant highway speeds, as I am sure that your engine RPM will be within that range.

With 3.73's and 15" tires, I would guess-timate about 3000 to 3200 RPM in 3rd gear at 65-70 MPH, right? (less with an overdrive trans)

If that is correct, then a stall convertor isn't going to hurt you much either.
If you're just worried about cruising at around 3,000 RPM then the cam and the heads are probably a bad idea!

The cam affects a lot at steady cruising, especially mileage and passing power. For a street only vehicle focused on cruising I would get your compression at about 9.5:1 with a cam about 205/210 duration and all the lift you can get. It won't lope and it'll have no balls past 5,000 RPM, BUT it is what you need for the best highway cruiser.

To really make the most of it bowl port the heads, consider going to a 30 seat angle (at least a 3 angle seat is a must, as is back cut valves), 1 1/2" long rube headers, a performer manifold and a good vacuum secondary carb. If well done you can get an easy 300hp at a low RPM.

The cam will definitely not work, the heads may work well depending on how much work you put into them, a 1.84" valve is more than adequate for this combo but the castings need cleaning up and compression should not exceed 9.5:1 if you want to run 87 octane.
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  #19 (permalink)  
Old 09-12-2012, 05:45 AM
How fast is fast enough?
 
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Originally Posted by bygddy View Post
So i followed every friggen post you have on porting the 416 heads lol, I have likely around 40+ hours in the friggen things..! I dropped them off yesterday at my machine shop and he called me back quickly. Turns out he is an older hotrod guy and loves these heads, he has been porting them and using them for years and absolutely loved the work I put into them and thinks they will work really well! He says they already had new bronze guides installed so he offered to install 194's at no additional charge as they hadntonbe re- seated anyways due to a couple slips with the die grinder. They are getting hot tanked, new valves, new seals, minor de- shouding due to the bigger valves, and assembled with my comp springs and appropriate shims.....out the door for 300$.....seems fair to me? I'm wondering, if anyone actually read this novel, if they could sim this combo to give me a rough idea of what to expect HP wise?
Heavily worked 416 heads
Perfomer intake port matched to 1205
1" Carb spacer
350 with flat tops using shim head gasket
Lunati bare bones cam pn# 10001k.
Duration 280/290, Lift .443/.465,*
Shorty headers
750 quad on top.
Thanks!
And p.s thanks a million f- bird for all your posts lol.

If you really opened them up a lot then a 1.94" valve can fit them well, BUT for a given flow using the smallest valve possible will result in more hp. Your parts are a bit mismatched, if you haven't ordered the cam yet I would go a little smaller- assuming your compression isn't too high, which it may be depending on the pistons.

A better matched engine will make the same power but at lower RPM. It won't sound as nasty or use as much fuel. Easier on parts too.
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smallblock383 (09-17-2012)
  #20 (permalink)  
Old 09-12-2012, 06:09 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
345 to 360hp. The shorty headers are going to cost you 10 to 15hp and some torque.
Long tubes are way better. The cam you got is a good match to the shorty headers. Needs a good exhaust system.

A drag strip test (MPH and known car weight w driver) will tell you how much HP you are really making.
I'm sightly concerned with the previous post saying my parts are " mismatched"? I selected a small cam, and that's actually the only part I "bought" lol...... everything else I had....but I figured the performer and these heads would work well with this cam? Hmmmmmmmm

F- bird, hey thanks for getting back to me, yah, for exhaust I'm running the Shortys straight down to "3 diameter, 6" dynomax bullits and to 3" side pipes, nothing else lol....so I suspect breathing won't be an issue? Although volume might be! It will hit the strip hopefully next weekend when I get it all back together.....Its in a 77 Vette, TH350, I believe a small converter, and 411 gear.....I will be happy as pie if it runs a low 14 or high 13.....
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  #21 (permalink)  
Old 09-13-2012, 06:36 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
Drag strip traction with street tires is going to be the limiting factor to a quick ET.
If you can get and use some sticky tires it will make a huge difference.

As I said the MPH tells the tale of horsepower produced.
You have only just started the tuning process to getting
to a decent ET/MPH. But its a good start.

Post your track results when you get them. (1/8th mile track data is fine)
Good luck
I do have access to the drag radials on my buddy's blown SBC vette so i may borrow those, my biggest concern right now in the Carb, I know zip about quads, I know its on the car now and works flawlessly, no bog, no stumble, no anything weird other then it seems slightly rich (smell and plug color) ....that being said I have a virtually new edel 1405 on the bench so i may try that......heads are being dropped off in the am so sat I will take it apart and should have it ready to run at the track next weekend.....
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smallblock383 (09-17-2012)
  #22 (permalink)  
Old 09-14-2012, 02:54 AM
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Quote:
Originally Posted by F-BIRD'88 View Post
The 305 heads on your 350 w a .480" cam will work fine.
Get a 3000+stall converter for the cam and recurve the distributor.
The cam will want gears too.

May need more than 87 octane.

Exactly which 305 heads do you got? casting number...
i have the 81's
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Old 09-14-2012, 09:49 AM
How fast is fast enough?
 
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If you're absolutely broke and can get free machine work then the 305 heads are an okay option (not really great though).

But I'd take those chinesium heads over them any day. Yea the small chambers help make good compression with a dished piston, but you can mill 64cc chambers to do that too

the 305 heads are super thin, have tiny ports, mediocre at best port and chamber design, a heat crossover passage that kills power, are worn out before you even get started on them, and require all new hardware.

So you can dump $400+ and 40+ hours into heads that will never be as good as even oem vortecs or just save a little more and get some budget aftermarket heads that are better in every respect.

I did the 416 heads once before. Total waste of time and money, but I had to learn the hard way.
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Old 09-15-2012, 12:44 AM
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Quote:
Originally Posted by F-BIRD'88 View Post
You are not going to go faster by putting a tiny carb on it
The rich smell is cureable. (heat, primary metering rod, timing curve, fuel pressure)

Performer manifolds always run too hot(smell rich) unless you get the heat riser flow corrected.
(especially with a AFB carb)
Block it off, or block one side and restrict the other side. (winter driving)

Get a wood carb spacer too. Heat isolation. I recomend a divided type wooden spacer for that manifold, for your car.

The RPM intake manifold is way better in every respect. It does everthing better than the performer manifold.

That and long tube headers should be on your wish list.

sell the performer and the tiny carb to someone that wants to run 14's.
To fund a RPM intake and corvette long tubes.

Now the cool low buck ported 305HO heads will suddenly be all they can be.
(and make a lot more power and torque)
The prob is I want to retain the side pipes so long tubes won't fly, well....want isn't the right word per say, its more part of my spend no money theory.....I will pick up some sheetmetal tommorow and make a small plate to block off the heat riser, would I be better off using the quad that's on it now as opposed to the small ede? I have a 1" spacer for the quadrajet but its composite instead of wood.....will that suffice? And I recall u saying I will need around 20degrees initial so I'm trying to find your post on how to restrict total timing, around 34-36 total and all in early correct? So medium springs and just need to learn the restrict part.....and then figure out how to start the damn thing with that much timing without spending on a gear reduction starter....I think I remember something about an ignition kill till it rolls over then hit the button to fire it but not sure if that will work with an hei. ....
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Old 09-15-2012, 12:58 AM
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I'm an idiot, found both your switch post and you advance limit posts, so for sake of argument, knowing im running 94 octane always, what's the PRo or con to just locking the timing in at say 36 always and running the ignition interrupt to start it?
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Old 09-15-2012, 06:37 AM
How fast is fast enough?
 
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Originally Posted by bygddy View Post
I'm an idiot, found both your switch post and you advance limit posts, so for sake of argument, knowing im running 94 octane always, what's the PRo or con to just locking the timing in at say 36 always and running the ignition interrupt to start it?
try running 36 under load at low rpm and you'll be buying pistons. That's the biggest disadvantage.
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Old 09-16-2012, 07:03 PM
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Originally Posted by F-BIRD'88 View Post
No you don;t want to lock out the timing on your motor.

16 to 20deg initial is about right with that mild cam. 34-36 total.
Check your HEI distributor it should have a 20deg mech advance curve now.
A 16 to 20deg curve is just right, on this one.

The short curve and or locked curve is intended for motors with much bigger duration cams.

There is nothing stopping you from running long tubes with side pipes.
The connecting pipe is U shaped. Ya it has to be custom fabricated.

A divided spacer is better on your motor. Fully Divided dual plane manifold plenum.
something you can work on.
Thanks for the advise, I really wasn't looking forward to screwing with the dist.
So far so good, everything's apart, other then some minor issues, header hits the starter, so will hit the wrecking yard for a factory GM mini starter, and for the second time in my life I forgot the bolt for the balancer so the puller trashed the first few threads, nothing a chase shouldn't fix tho....



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Old 09-16-2012, 07:05 PM
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And yes, that's absolutely a 5pnd sledge on the left and a sawzall on the right, I don't fk around!
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Old 09-17-2012, 09:59 AM
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Quote:
Originally Posted by F-BIRD'88 View Post
This is all BS....
AP72 is right. I would not waste my money on a set of thin casting 305 heads if Santa Clause would drop it on my lap. There are better aftermarket heads that will be cost effective and get far better torque and horsepower not to mention higher RPM (pass 5000 RPM). I had a set of 202 heads and you know where it end up? Staten Island Dumps. It was cost effective buying a set of AFR heads.

Last edited by lg1969; 09-17-2012 at 10:06 AM.
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Old 09-17-2012, 10:18 AM
How fast is fast enough?
 
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AP72 is right. I would not waste my money on a set of thin casting 305 heads if Santa Clause would drop it on my lap. There are better aftermarket heads that will be cost effective and get far better torque and horsepower not to mention higher RPM (pass 5000 RPM). I had a set of 202 heads and you know where it end up? Staten Island Dumps. It was cost effective buying a set of AFR heads.
If you're talking about the old "camel hump" 2.02's, while they are not great by any means they're also not nearly as bad as 416's. I would have at least tried to sell them on ebay for $50 or scrap em out.

There's also a BIG gap between top of the line AFR's and the cost to rebuild stock heads. AFR's are nice but there are a lot of other less costly aftermarket heads to consider too.

FWIW I was once dumb enough to be duped into the whole 416 heads with porting and valves thing... I learned my lesson the hard way.
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