vortec port reshaping-poss. or pure insanity?

[no_doz]

i recently saw my machinist buddy & we got to talking & ever since ive been kinda curious about something. he has all the tools-would it be possible (if i give him a a 4.3 vortec head & a 3100/3400 head) for my machinist buddy to reshape the combustion chamber to match as they are on the 4.3 (but a tad smaller & ratio'd properly due to the 4.3 bore being .38" bigger) to actually end up with a 3400 vortec? im sure that he has all the tools needed -if- this is possible, but what im not sure about is can the heads be welded on without warping the head-so long as its "decked" (or whatever the proper term would be) to make sure that the head/block mating surfaces were both flush & even afterwards? if its feasible & just requires knowledge & tools im sure hes got it, but he doesnt get off work till 8 tonight & i dont want to straight up ask em before i see what you guys think.

[SappySE107]

Stop doing drugs.

[no_doz]

well you could have atleast said no way in hell & gave me a reason, hell i dont know-thats why im asking you guys.

[SappySE107]

Vortec top right, non vortec top left, 3400 bottom. Vortec is not splayed valve, meaning the valve just go parallel to the bore. 3400 move the valve further from the chamber edge and cylinder walls as it opens.

[no_doz]

thank you so much for this!! i do realize that the orientation of the valves would need to remain the same-but what im curious about is could i have him just reshape the combustion chamber a bit as shown (yes, its a rough i made with windows paint :P)? looking at it i dont see anywhere that would need added-just removed & reshaped. please let me know what you think & if its a dumb idea can you please continue to show me as to why like you have been?

thanks ben!!

[geoffinbc]

Vortec is just a name. The chamber design is the same for all the fast burn heads which is all a Vortec head is. The large quench area is what causes the swirl in the head. When the piston arrives at TDC the gases in the quench area get squished out into the heart shaped area around the valves and spark plug, causing the gases to swirl and mix better. So save your money.

[no_doz]

wow-you never cease to amaze me with your in depth & highly technical yet accurate answers. is the combustion chamber design on the 2000+ 3400's efficient as the true vortec heads? i say efficient because i didnt want to say good and sound like even more of an idiot than i probably already do! :P

[robertisaar]

vortec 4.3s make like what 200 HP from 4.3 liters while 3.4s make what 180?


the calculator says
0.046511627906976744186046511627907 hp from 1 cc on 4.3
0.052941176470588235294117647058824 hp from 1 cc on 3.4


i realize heads don't determine everything, but when it comes to hp/displacment.... the 3.4 is winning

if the 4.3 made as much power/disp as the 3.4 it would be making around 230HP

[SappySE107]

I don't know who did this amazing work but I would copy it if you copied anything...

[no_doz]

i realize this but i hear all the time how vortec is one of the most efficient designs that you can find & it didnt seem like too much to remove a little metal considering half the engine building articles i read-at some point they usually reshape the combustion chambers.

is that a reshaped chamber?

[robertisaar]

i realize this but i hear all the time how vortec is one of the most efficient designs that you can find & it didnt seem like too much to remove a little metal considering half the engine building articles i read-at some point they usually reshape the combustion chambers.

is that a reshaped chamber?

vortec might be the most efficient design for a SBC... or a 4.3(since its based off of a SBC), but 3400 heads are damn good designs compared to earlier stuff.

[Superdave]

Vortec heads aren't all about the chambers, it's port flow as well. That's why they are better than the old SBC heads. Same reason why Gen3 heads are better than Gen1 iron heads.

Leave the combustion chambers alone.

[geoffinbc]

I don't think you got the point of my post. A Gen III head is a "Vortec" head, hell even a Gen II head is. The Gen III heads are as good as it gets and even BETTER than a "Vortec" 4.3L head since it has splayed valves and is made of aluminum. The heart shaped chamber with a large quench is what makes the power.

Like I said "Vortec" is just a name. For example the LS1 or LS6 in the Vette was called just that. But the 5.3L and 6.0L in the truck with the same head was called a "Vortec" motor. Even though the "Vortec" name started with Gen I small blocks, skipped right over the Gen II small block since it was never used in a truck and now the name is applied to the Gen III and IV small blocks, which in current trucks is a direct copy of their LS counterparts. So get over the name and stick with a stock head. Don't mill out the combustion chamber because you will lower compression and most likely hit a water jacket and then your screwed because scrap prices are so low you wont get dick for them.

[no_doz]

lol well that answers that question! :P