Red 253 On Lpg

[vintageholden]

what mods do you recomend
i,m getting a crow lpg cam
i have impco 425 carby on 4bl base plate
hi rise manifold
impco model L mixer
extractors twin exhaust
electric dizzy


whats next??????

going in my eh ute.........

porting etc
thanks for the help on my 202 turbo project
keith

[sean]

Only mod I'd recomend is to your post...
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[vintageholden]

Only mod I'd recomend is to your post...

meaning what????????????????/

[sean]

meaning what????????????????/

Meaning that you use capitol leters to much.

There are a lot of guys on this forum, that know a lot about this topic, and if you re write your post without the capitols people will actually read it.

Also try searching Jmac, he's posted enough on this forum about Holdens on Gas to write a few books

Sean
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BUY VAPIR ONE

[vintageholden]

so i had my caps lock on BIG DEAL.......................

[jmac]

ok - top of my head - I'm pretty sure the squarebore holleys bolt to a 425 - AND the spreadbore. If that _is_ the case use the spreadbore holley base so it fits the manifold without adapter plate and without it rising up high enough to prevent a tall airfilter going on there.

If you haven't got it already, don't get too fussed about an aftermarket inlet manifold, run the factory 4 barrel, and do some _very_ light work around the carb base area radius any sharp edges.

Run later model hei.

Try and find 1 1/2 inch primary extractors, which might require to take a die grinder to the extractor flanges to taper them from the port exit down to the main primary pipe size. If you run 1 5/8 you'll lose some serious potential mid range.

Run a model E convertor. The L is not able to cope with more than around 200bhp continuous. It's right on the borderline. It'd probably just cope since the 253 won't make a hell of a lot of power, but personally I would go with the model E.

If you are going to get a non standard cam, I'd actually suggest not going to what is termed an lpg cam. It's just one of the mildest grinds around being relabelled to make a sale (and I'm not talking about crow cams specifically here). It'll likely have bugger all duration, only marginally better than stock. Of course you can't go really big or it'll be an undrivable frustrating pig. Look for something around 210 degrees duration at 0.050" lift as the biggest to go for. Yes I have seen people run bigger but I wouldn't recommend it.

Honestly - I wouldn't spend money on the cam at all. I'd instead look around for a s/h 308 block and put in there instead. A mild or near stock 308 will happily outpace a more modified 253

[vintageholden]

thanks again

keith

i have a 253 in the shed, just wondered if it was a better option than a 202 turbo

[vintageholden]

i have a 308 now blue motor
still the same applies????
extractors etc

[jmac]

Differences off the top of my head:

1 5/8" extractors will 'work' on a mild 308 so if that's what you can find, no big deal. C

You can go for a little more cam duration and the bigger motor will not be as hairy. Or put another way, the same cam duration will get you a very well mannered engine with lots of mid range, that a 253 would be slightly peaky with.

Look around the twin 2 1/4" exhaust size from the collectors on back, and if you can manage it, an x-pipe will get you around 5-10 ft lbs, but importantly across a reasonably decent rpm range, not just a peak figure.

[out_in_front]

Best mod to a 253 is a boat floating above it...

308 will be much better.
Are you doing the install yourself or paying for the job? Would it be worth looking at a SGVI or Pure Injected setup?