Good point.

One should always plan for a combonation with proven part's, never narrow your standards to statiticians. No one cares what your engine dyno's or your head flows, unless it proves itself on the track.

 

Your link does not bring ya to the specific thread.
Need some help.....

Works for me.

Maybe you have to register to get to the advanced engine tech forum. I guess I didn't think if that.

It might be worthwhile to register on that site. It's a good source of info.

www.speedtalk.com/forum

tom

 

I also believe that this has to be a DIY'er kind of thing as far as the porting and a few of the other mods are concerned or the bang for the buck get reduced in a hurray.

This is probably the most pertinent part to me. If the guys bringing me the heads could do their own work, I wouldn't be seeing them. To take the time to install the bigger valves, unshroud the chamber, blend in the bowls, open the intake ports to the gaskets and blend in from there, do a performance valve grind, install screw-in studs and guide plates, valve guides etc., they would probably cost as much as or more than obtaining a good set of aftermarket heads with more flow potential. Also, the end result would still be a set of OEM crack-prone heads.

Here is a telling comment from the Speedtalk thread:

"I see a lot of guys get greedy for big valves in stock style heads and they cut the seats and bowl hog the throat area out and then just kinda blend everything. Well now the smallest cross sectional area is way up inside the port somewhere and the whole combination is just wrong from a flow standpoint. I would do everything I could to avoid that if I were attempting to make an engine that runs well."

So basically the 305 heads are not the best place to start from a high-performance standpoint. Even when flowed to the max, they are handicapped by the lightweight casting and less than ideal balance between raw flow and port design. If one had to pay to make these heads flow as good as much as a good aftermarket head and have the supporing work done, it would not be a cost-effective excercise. If one could do most or all of the work himself, why not do it to a head better suited to the job at hand?

The heads I am referring to are the 601 casting or equivalent, 1.84"/1.50" valves, 54-56 ccs.

tom

 

I look for the 416's.
Well I appoligise in advance if ya happen get some people showing up at your shop with a set of greasy old 305 heads wanting you to do it all and make them just like this F-Bird' guy does, for basicly peanuts.

I do, and advice to do all the dirty, ugly work yourself at home like pass on the screwin studs and just drill and pin them yourself.
and get the machinist to do the stuff that take precision machining and training.

No problem. I can usually disavow them of that sillyness with little effort.

tom

 

Here is a telling comment from the Speedtalk thread:

"I see a lot of guys get greedy for big valves in stock style heads and they cut the seats and bowl hog the throat area out and then just kinda blend everything. Well now the smallest cross sectional area is way up inside the port somewhere and the whole combination is just wrong from a flow standpoint. I would do everything I could to avoid that if I were attempting to make an engine that runs well."


tom

What happens with these people is that they just cannot visualize how "flow" actually works. They seem to think along the lines that bigger is better, no matter the application.

Now, in all fairness, not everyone can properley "see" things the way some can. That is why this board exists...to help the less knowledgable learn.

I can attest that as far as myself I am still stuck in the old school mentality, and have been learning a lot from all of you in regards to advancements that have taken place in the past decade or so.

Thanks for the read Tom.

 

What happens with these people is that they just cannot visualize how "flow" actually works. They seem to think along the lines that bigger is better, no matter the application.

Now, in all fairness, not everyone can properley "see" things the way some can. That is why this board exists...to help the less knowledgable learn.

I can attest that as far as myself I am still stuck in the old school mentality, and have been learning a lot from all of you in regards to advancements that have taken place in the past decade or so.

Thanks for the read Tom.

No problem. I certainly don't pretend to know near as much as those real pros do.

Just to put clarify and put credit where it is due, this quote:

"I see a lot of guys get greedy for big valves in stock style heads and they cut the seats and bowl hog the throat area out and then just kinda blend everything. Well now the smallest cross sectional area is way up inside the port somewhere and the whole combination is just wrong from a flow standpoint. I would do everything I could to avoid that if I were attempting to make an engine that runs well."

was posted by a certain SWB, a member of the Speedtalk community.

tom

 

OK so now that everybody is playing relatively nice in regard to 305 heads which would be a better head for a mild 350 daily driver limited to a max RPM of 5,000 or so that will rarely see the high side of 4500, '416 305 HO heads or a set of '193 Swirl Ports off a 350 TBI? Those are the only two options, this is not a performance engine in fact fuel economy and low end throttle response are more important with low cost being the key factor. I need to put a CHEAP 350 together for a driver out of what I have available and I have a decent pair of each and the right pistons to make either one 87 Octane compatible.

 

... (W)hich would be a better head for a mild 350 daily driver limited to a max RPM of 5,000 or so that will rarely see the high side of 4500, '416 305 HO heads or a set of '193 Swirl Ports off a 350 TBI? Those are the only two options, this is not a performance engine in fact fuel economy and low end throttle response are more important with low cost being the key factor. I need to put a CHEAP 350 together for a driver out of what I have available and I have a decent pair of each and the right pistons to make either one 87 Octane compatible.

You made it easy to answer: cheap 350, 87 octane, fuel economy, low cost etc

The detail:

The 193s won't suffer a drop in CR because they're going onto a 350. (edit: the 416s have a smaller chamber, so the CR will increase when using them on a 350.... and that could cause a problem with using 87 octane depending on the load on the engine).

The 416s have more of an open chamber and flush mount of the spark plug in contrast to the 193s (better squish region, projected plug placement) and that shows in the spark advance used on both heads: 34-36 degs advance on the 416s vs 30 deg or less (depending on the application) for the 193s. IOW the 193s are a fast burn design (central plug location, high swirl to speed the burn) and the 416s aren't.

The 416s obviously flow better on the intake and more poorly on the exhaust than the 193s do, but that can be fixed with a little DIY porting work. You mentioned fuel economy, low end throttle response and low expense as being important so I think the decision should be an easy one to make.

Also read this thread before you decide:

http://www.thirdgen.org/techboard/tbi/336750-tbi-tpi-heads-headflow.html

 

The 193s won't suffer a drop in CR because they're going onto a 350. The 416s will.

The 416s have more of an open chamber and flush mount of the spark plug in contrast to the 193s (better squish region, projected plug placement)

Thanks for the info. The 193's are 64cc chambers, the 416's are 58 or so. The 416's would raise compression IF I used the same pistons which I wouldn't. Since both sets of pistons available have a full dish quench area is a moot point and I don't plan on porting either set. This will be a basic valve job and bolt 'em on and go motor. I'm saving all the "details" and $$$ for the good 355 I'm building with Vortec heads and D-cups.

 

If you're on a budget, I suggest, instead of 305 heads, a used 500 cad and a bottle of juice.



No porting, no fuss, no mess.



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