b0b

iTrader: (1)

What is the stock size for valves in a 799/243? I have looked all over tech and havnt found the answer. 2.02/1.60??

KCS

iTrader: (20)

2.00"/1.55"

Link

wildcamaro

iTrader: (15)

^yes sir

3rdCoastPowerSports

iTrader: (5)

x3.....

b0b

iTrader: (1)

Thanks guys, just mic'd them to make sure I had stockers

wildcamaro

iTrader: (15)

Bigger valves aren't even worth the money....it's so funny when i tell an old school Chevy guy I have 2.00/1.55 valves and they tell me they have double humps and that have 2.02/1.60, then I ask if they wanna race lol

KCS

iTrader: (20)

I would have to disagree. I've seen through first hand experience (not pulling graphs off the internet) that the bigger valves made more power with the same valve job, even more so compared to a stock valve job.

wildcamaro

iTrader: (15)

Conventional thinking makes me believe for the price of the valves and accompanying valve job it's not proportional to the performance gain, but I would be interested to know why kind of results you got an what size valves you upgraded to

bww3588

iTrader: (49)

The stock valve job is crap. There is quite a bit of power to be had with a good valve job, and a back cut into the port. This is all without changing valves or sizes.

RonSSNova

iTrader: (3)

Ok, good info.

Are the seat widths and angles a secret?
Do you know what they are?

Typically, a slightly larger valve lets you manipulate the valve seat in the head.

Ron

KCS

iTrader: (20)

10-40whp between a 2" valve and a 2.02" valve, depending on the application.

Which is why the biggest gains are when you go from a stock valve job. The seat diameters are often cut undersized to allow room for the seat to wear, but if you lap in an 80k mile valvejob, there isn't much wear in these powdered metal seats at all. So, I like to cut the valve job to the valve diameter.

If you're already getting a valvejob, a set of 2.02" intakes are only about $100 from REV. The exhausts will probably need to be replaced anyways because the tips like to crack.

KCS

iTrader: (20)

Another good point, except I want to add that you can open up the throat without such an abrupt transition into the chamber. Some people like to use a general rule of thumb of about 90% of the valve diameter, so a 2" valve would allow you a 1.80" diameter throat (2.54 sq in). Cutting a 2.02" will allow a 1.818" diameter throat (2.6 sq in). That's a significant increase in area.

wildcamaro

iTrader: (15)

Good info, I would of never thought such gains from such a small increase...so are you saying those gains are from just a 0.020" increase in intake valve and leaving the 1.55" exhaust?

I still will put my 2.00/1.55 up against a double hump 2.02/1.60 any day lol...put that's apples to oranges I guess

KCS

iTrader: (20)

Yep. Just cutting the VJ and throwing in the valves will likely get you gains on the low side. Opening the port for the larger valve and a larger cam/more RPM will get you more.