Holley 350 rejetting

[Anonymous]

Got a Holley 350 from a carb shop on ebay. It was rebuilt professionally and test run on the shop's own 350ci inch engine. Guy said it ran like crap and was way too rich which he was not able to correct with the mixture screw on the carb.

It was rejetted with a 65 main and a 6.5 power valve as suggested by guys on the forum.

Whats going on here?

 

[Anonymous]

Wow I have never seen it so quiet.

Can anyone help me out?

 

[alloydave]

Hello Spyke , i dont have the answer your looking for ...but .There is a
Holley website that does give some good info on jetting sizes on a rpm vs cubic inch chart that might get you a bit closer to the target.

 

[xctasy]

Three things.

Never tune by Louis Braille or Louis Chevrolet.

Secondly, the power valve channels are sized for a V8, and can be reduced first up with a fuse wire. This reduced the excessive rich condition under wide open throttle.

Thirdly, you can drop back to a 59 or the stock fitment 61 jet to see if it really is running rich.


Heres the limits:-


If the engine is rock stock, you can drop down to 56, a 2.0 power valve, and restrict the power valve channels to 17 thou and still get a target 120 hp in a little 200 x-flow.

When you've got 25% more capacity, you can go on up to well over 63 for a 250 with extractors. Its not hard to get over well over 150 hp with a 350 cfm carb. If its really running that rich, back off to to 61. If its still rich, go to 59 jets

Read wsaIII's posts, and add some fuse wire to the power valve channel restrictions.


My mates with 202 Holdens with a good 265 degree cam can run 63's and 6.5 power valves and that's well over 150 hp with ease, and no other mods.

The 250 X-flow should really like a good jet size.

A SBC is a different animal. 350 V8's like 500 cfm carbs, and the old 2 jet on 327's and 350's was often about 470 cfm, not 350 cfm. A stock 350 retro fitted with an old 327 2-bbl intake and Holley adaptor with a 350 2-bbl sees about 168 hp at the flywheel. A good 500 takes it up to 185 hp, and 227 hp is possible with heders according to the Australian Lynx industries power games series in 1988.

 

[Anonymous]

I just put a 350 holley on my 200 xflow.

havent got the jetting right, i have an un-numbered power valve (how can you tell with out the numbers?) and 53-2 (the two is upside down, what does that mean?)

It seems to lean out at 35kpa manifold pressure, but its only done this since ive gone down to the 30cc throttle pump from the 50cc one.

it runs well with the 60 jets and 8.5 power valve, but its way too rich like that, plugs were black and tail pipe was filthy, stained my driveway actually...

with the fuse wire in restricting the power valve, does open the power valve earlier or later?

ive just purchased myself an o2 sensor which ill have up and running soon, should screw into where the egr valve was, that should help me get the jetting perfect

 

[xctasy]

The power valve opens the same vaccum no matter what size fuse wire you use. The lower the number, the less time it will be open. On little 4 cylinder Pintos, a 350 Holley can run a 2.0 powervalve, and the Power Valve Channel restrictions can be dropped to 16 to 19 thou from the stock 56 thou or so.

The 350 cfm 2-bbl was designed for a 327 Chev or FE Ford V8, so it is way rich with two 56 thou holes on our little I6's. If you shove some thicker 10 to 15 thou fuse wire in the two holes, you'll lean the wide open throttle richness down a satisfactory amount.


You must read wsa111's posts, and try dialing the power valve down to 6.5, and restrict the two power valve channel restrictions. Main jets on a 200 can be right down to 58 to 63. On a 250, it likes more jet. 63 to 65 is common. A 250 x-flow comes alive with a Holley carb. The 200 log head also shows a huge boost with the right adaptor and exhast.

 

[Anonymous]

Ive been trying to find this post by wsaiii that you keep talking about but i cant find it...

can you search and see if you can find it?

so what does reducing the restrictors do?

 

[xctasy]

wsa111 has this profile http://fordsix.com/forum/profile.php?mode=viewprofile&u=2203

wsaiii hasn't been invented yet.

Open all postsby wsa111

http://fordsix.com/forum/search.php?search_author=wsa111

and view everything he says.

Great stuff for a Lexus dealer.

 

[Anonymous]

alot of good reading there, i saw the one i was looking for too.

now i need help identifying these power valves.

i have two here.

one is marked 8 5 4 T

the other 8 5 8 D

 

[xctasy]

There are a few differnt kinds of power valve. Picture window, older type, and the post 1976 item.

On V8's running up to 300 or more hp with a big car, some power valves rated at 85 have trouble delivering enough fuel through to the Power Valve channel restrictions because the slot in the power valve is too small.

I'm not sure what the difference is in code. Generally, any later power valve fits, and as long as its 8.5, then it reads 85 for the first two numbers.

 

[Anonymous]

i put a B string in the PVCR's today, i think i had super lights on my guitar so that should be about .010" or .011" my E is either .008" or .009" if you'd recommend that ill put it in instead.

it ran well, i drove about 30 k's parked, did what i had to do and drove off and then it back fired. been running like crap since.

im guessing i blew the power valve, leaning the idle right off doesnt kill the engine either. is there a way to tell by physically looking at the power valve?

i havent taken it out yet.

it was idling at about 51kpa, which is about 15"Hg

should i get a 6.5 or 7.5?

whats the difference between the standard flow and high flow power valves?

 

[xctasy]

Ha ha ha. Tuning by braile! Not a good idea, as the Holley has bulk adjustability in it, and little things can mess it up.

The tuning of a Holley can be a wander about all sorts of issues, so I'll have to be specific.

1. Generally, the later Holleys have a ball check valve as a blow-out protector. You can get a kit to fit one, its comparitively easy to do with basic tools.

2. The 200 likes to have 58 to 63's at most. 60 sounds okay, but if its too rich then you must lean it off. When you have Close Limit Emissions jets, 532, which is the standard jet for front half of 390 cfm 4-bbls, its a little bit too lean. The lean-off of the PVCR if the 60 jets are rich isn't a bad idea, and so use the thicker guitar wire.

I think that the right jet for a stock 200 should be about 56 to 58, and you can run any power valve that suits. So stick with 8.5 meantime. The restriction has to be based on a fuel air meter at wide open throttle.

 

[Anonymous]

ive been trying to get this damned oxygen sensor in there for weeks, i dont get much free time and i have no garage so i can on work on the car during clear days...

i need to get a 15mm drill bit (bunnings dont sell them btw) to drill out the egr hole in the exhaust manifold to make it fit.

the carby i have wont be post 1992 built. what does the blow out protection look like and what does a blown power valve look like?

p.s. the exhaust stinks of fuel at idle (you can smell it from the drivers seat if you have the window down) and the idle screws are 3/4 of a turn out...