LilJayV10

iTrader: (39)

I would be interested in seeing what the difference in power is between a good valve job vs. full on port job.

outkast6991

iTrader: (34)

send me a set of cnc'd deals and i'll let you know. my vj/bowl work only heads made good power and my head guy was honest about spending anymore money on the heads. dollar per hp the vj/bowl combo is the way to go. if you want every hp out of your setup find somebody with a good port and spend the cash for it. a good vj/bowl blend is about 80-85% of the potenail of the head. the other 15-20% get a little more pricey

LilJayV10

iTrader: (39)

Well hell. I stand by my worst hp/dollar mod yet!

A.R. Shale Targa

iTrader: (2)

Another aspect to consider is an LS1 intake or even an LS6 begins to hinder
flow potential @ 250/265 cfm respectively. So bolting on a head that flows
around 300 chokes what it's trying to accomplish. I'd say this is why so many
on this forum have tremendous results with a good valvejob on 243/799 heads
which end up in the 260-270 range. This is also enough CFM to feed a 346"
engine to 6500 RPMs and roughly 500 flywheel horsepower.

Cosmos

iTrader: (15)

You got proof or you just a follower saying that because AI is the flavor of the week?

Beaflag VonRathburg

iTrader: (176)

Read quotes.

ggino85

iTrader: (1)

quick question, (i hope the op doesnt mind, its in the ballpark of his question) i just got my 243 heads back from getting a valve job and resurfaced aswell (took .010 off each head), does that meen i will have more hp/trq than if i would have just bolted them on without doing the valve job. i only got the valve done because i bought the heads used and wanted to make sure everything was ok.....the shop told me the price to give them a full valve job isnt much more than it is for them to take apart and "check" everything so i just went ahead and had them do a valve job.......if i picked up extra hp or trq that would be awesome! thanks gino.

Evans752

iTrader: (29)

This is interesting deal here for me a looks like a few others, I have been putting pack for either getting my LS6 243 heads CNC ported and done up by TEA in Ohio and had forgot about AI in North Carolina or to buy a set of the Trick Flow 215 CNC heads but getting my 243 LS6 heads CNC'd and done up would be half or less in price and if I could get a REAL CLOSE flow numbers or the best at doing them info and opinion like alot of you all here as it looks would be GREAT. TEA has there flow numbers on there website and would like to see the flow numbers for AI if someone has them, I know with my stock lower bottom end motor can flow TOO MUCH and LOOSE POWER, been there and done that years ago with my past LT1 Camaro when I bought 195 LT4 heads and was two young and STUPID LOL not to know better. THANKS and hope everyone has got the info out of the noce peoples answers they looked at.

PREDATOR-Z

Yes, but saying that all the rest of the porting job is only worth 10 Hp is a bit extreme. If I had to put a value I would say more like "would be worth approximately 35% of gains"

01ssreda4

iTrader: (96)

Re-machining the valve seats (what you had done) and a "valve job" are two different things in the context of this discussion. Re-machining the seats gains no hp.

A.R. Shale Targa

iTrader: (2)

Completely hypothetical breakdown by someone who can't spell CNC........
Cam and bolt ons car dynos XXX w/stock 853/241 heads.
A freshly cnc'd ported set of 243/799 from either AI or TEA bolted down and
retuned gives you 60 rwhp....equals happy camper right ?????
Lets NOT assess how much the tune was worth since it's a necessity for both
combinations to make proper power.
Will most agree that the improved casting in stock from GM form was prolly
worth the first 25 horse ????
The remaining 35 will have come from these different improvements:
.....CNC intake runner (increased volume, shape enhanced, rocker bump gone)
.....CNC valve bowl/guide shape enhancement
.....CNC combustion chamber to unshroud the valves
.....Milling 0.xxx to get them flat and increase compression ratio
.....Valves ground/backcut; multiangle valve job on IN., radius cut EX. seat
I'd bet a bump in compression of 6 tenths (since the 64.45cc VS. 67.67 cc
already kicked it up from 10.19 to 10.45) so lets assume a final chamber of
61-62 cc puts the final comp @ around 10.8........maybe 5-7 horsepower
I will purely guess that ALL the CNC work attributed for about 20 of the
remaining 28 improvement...putting a quality valve job @ 1 h.p./ cylinder=8
After years of building Vortec truck headed circle-track engines I believe
the GM valvejob is decent for production. When someone pulls their old heads
for a freshen-up, they're more than likely getting them milled and a good
valve and seat work seems huge when the factory job has diminished in it's
ability to flow air/fuel and seal combustion. i.e seats get wide and hammered
from cam/spring changes and higher rpm's of usage.

LilJayV10

iTrader: (39)

studderin

iTrader: (28)

Its kinda true.

I have worked on cars with the $9-1000 CNC ported stock valve head, that have gained 15 hp and some gain 40hp with the SAME casting and CNC work from the same place??? some 420 others 450whp? When stock 243s always add 20whp for $400-550. And done some VJ and blend ($300-350) to the top of the guild on LS1 heads that added 30-35hp, 440/450 whp. These were all 10bolt m6 cars, with streetsweeper cam with bolt ons. I have thew dynos ans pics of the heads too.

RoidedSS

Give TEA or AI a call and ask what they think...since your heads will be off maybe either of those companies will do a VJ for you while they CNC your heads for a good price. I understand your on a budget but why not maximize the potential of the head. to the original question, if you can find someone to do a valvejob for cheap that would probably be your best bang for the buck. However, I would still call the professionals who most likely have experience with the question you are proposing. I will be sending my 243's to AI to have them CNC'd in the future and will post results. Goodluck with Whichever route you go.