304 355 Stroker Kit Help

[304RR]

The current 304 I have in the Range Rover has 10:1 compression a small 202 @ 50" cam and 4 barrel manifold. I had a Rochester on it but removed it and put an Impco 425 on. I think I lost about 50hp and a lot of torque. The idle mixture I tuned with my Gunson Gastester, to 2% CO, but cannot work out how to set the other mixture screw.

 

[EYY]

You won’t lose torque with lpg (noticeably) but airflow at upper rpm will be limited. You need to get the mixture right using a wideband o2 sensor. A single model E converter will be adequate or even a b2.

Sometimes you may need to change the diaphragm to get the correct mixture.

Is yours a clean air model? Does it have tamper proof (cap screw) adjustment or does it have the screw (idle) and hex (power) adjusters?

With such a small cam you shouldn’t notice a difference in low down power. I have one on my 308 with 206/[email protected] around .480 lift, Ported VL big valve heads, performer manifold, 10:1 comp approx, extractors etc etc. Has considerably more bottom end and mid than my efi 304 on injected LPG with crane 268, pacies etc. but the 304 is happier to rev, although I think that’s due to heads and intake design rather than fuel system.

 

[304RR]

The 425 I have has hex key adjustments for both the idle and power adjustments. They are set quite deeply into the body of the 425, you can access them through a round plate with a small hole in the centre.

 

[EYY]

The 425 I have has hex key adjustments for both the idle and power adjustments. They are set quite deeply into the body of the 425, you can access them through a round plate with a small hole in the centre.

Yeah that’s a pollution model. Will run quite lean as they have a diaphragm with the larger ‘needle’. For these models, the converter is connected to manifold with 3/16 hose via a couple of computer controlled solenoids so that the more modern systems could comply with emissions standards.

 

[304RR]

I have the B2 converter and a single 1 inch diameter hose connecting the converter to the Impco 425.

 

[304RR]

For the power mixture screw, how many turns in from the fully out position is the factory setting. I need to do this from the fully out position as it is hard for me to tell the fully in position. It gets quite hard to turn in the further I go, I am not sure if it will go in further or if something will break.