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post #1 of 7 (permalink) Old 08-31-04, 10:17 PM Thread Starter
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Question alloy head 4.1 mods

At some stage soon I intend to start on my new project car (xe faclon). I wont bore you with body mods but I will ask about engine.

I will use it as a daily driver. I will use a carby 4.1 alloy head six. I just want a simple car with no efi worries (e.g. chip upgrades, airflow meters, injectors etc etc.), reasonable economy (hence a six over and a v8) and some extra performance. The car will be manual.

My ideas
Shave head, Polish ports, extractors with 2.25/2.5 exhaust, small cam (around 25/65???) standard webber (maybe re-jetted). Will this give me a noticeable boost (e.g. 130kw over the 100kw standard)? What cam should I use??

Idea two.
Shave head, port head, polish ports, standard size valves with roller rockers, redline manifold (or match port the original), extractors, exhaust upgrade, mild cam. (will double valve springs be enough? Or do I need the roller rockers)

Idea three
as per idea two but add lightened flywheel, thermo fan and possible holley 350. (will these mods make that much difference???)

Idea four.
C.O.M.E st2 cylinder head and cam, with sports manifold, exhaust extractors etc.

As you can see the, each idea is a step up in cost (and performance). But what mods will give me the best bang for my buck?? Obviously if I spend 5000k on the engine it will go great but I am not rich so I'd like to add some go. Will idea 1 yeild results? Are the standard ports big enough? Is it worth spending $$ on thermos and flywheels?

Ultimately idea 4 is the best idea but how much? I have sent away for a price list but to no avail. Any aussie falcon owners got comments?

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post #2 of 7 (permalink) Old 09-01-04, 02:24 AM
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Re: alloy head 4.1 mods

ideas up to 2 plus a set of triple sidedraught carburettors.

Ford to Victory!
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post #3 of 7 (permalink) Old 09-01-04, 03:12 AM
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Re: alloy head 4.1 mods

I know you said you didn't want EFI hassles but I got the idea you were talking about EFI upgrades. How about dropping an EA MPEFI/EECIV in with 130 odd KW's stock?

I would think for under $2K you would have your power target, better drivability than a warmed 4.1 and better fuel economy.

Reason for EA MPEFI is they didn't have Smartlock or dual tract inlet. You could go further and use an EA EECIV on a EF donk, but you probably won't get 157kw's due to not running dual inlet.

Just an option worth cosidering due to good bang for bucks and reasonably easy to do.
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post #4 of 7 (permalink) Old 09-01-04, 05:16 PM Thread Starter
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Re: alloy head 4.1 mods

I will be doing this work myself and I don't know enough about efi and computers. I used to own an mpi ea 5 speed and it flew. I also thought about an ea motor with a carby on it, but i need mod plates and at least a t5 manual and this turns into cost. I can polish ports, fit cam etc myself. I can even have them ported free of charge. If I knew how to plug in an eec4 I would love to fit an ea, built to jim mock spec but I wouldn't know where to start. Any forum threads on how to do this? (ea efi eec4 into carby falcon)
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post #5 of 7 (permalink) Old 09-01-04, 06:43 PM
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Re: alloy head 4.1 mods

I'ts been discussed before in Fordforums, might be worth doing a bit of a search or start a thread on it. I think its a fairly easy job and would certainly tackle it myself.

As for the EECIV. Use the EEC wiring loom from the donor car, starter motor is on passenger side so grab battery cable and possibly the loom, use EA's radiator. Not sure about accelerator linkage, but XG ute is XF with OHC so thats another source of parts. Check fuel pump pressures as well, MPEFI has higher pressure pump than CPEFI so get EA pump.

Exhaust would require a small amout of rejigging that any exhaust joint coud do, or possibly use XG engine downpipe or you might go extractors anyway.

In a comparitively light XF, the OHC donk would turn it into a flyer.
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post #6 of 7 (permalink) Old 11-13-04, 08:38 PM
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Re: alloy head 4.1 mods

Hey Kieron, are you the Kieron?
Anyway to the question...kierons right about the efi engine being a quick relatively easy to get a nice reliable economical car. I have a bit of a soft spot for the old sixes, so I personally would rather go that way. I'd suggest a 30/70 ish cam at least, I had a 25/65 and it didn't affect driveability in the slightest and I always wished I'd gone further. I'd probably go 35/75 as you've got 4L to soak up the lumpiness (I like 'em a little angry too). There are about 7 different sizes and shapes of 'chambers in the cross flow heads, so I'd go to a wrecker and find one of the nice closed chamber jobies (well thats what they look like)and get that cleaned up. Good valve springs, wouldn;t really worry about roller rockers unless you're going to go all out and you're going to peen or uprade the rods, balace it etc etc. I'd suggest a 500 holley, 350 if you're worried about economy, with tuned length extractors and 2 1/4 system. Webbers will get you more power but need a lot more work in tuning and seem to be a lot more cantankerous in general, and I think economy would suffer. That should make for a mildly grumpy motor thats going to scare a few people and be a bit of fun to drive :D
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post #7 of 7 (permalink) Old 02-13-06, 12:22 AM
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Re: alloy head 4.1 mods

if you want serious horse power out of the 4.1 efi, you need to throw away the standard low comp pistons and put in near flat top xb pistons which will give you higher compression, but you will then need to modify your efi head as i did to match the higher comp. Ehat i did was to get perfectune to port and polish the inlet ports fit larger valves and stronger valve springs and open up the combustion chambers by cc'ing to equalize volumes to lower the comp to about 10.1, This auto motor with standard diff (2.92)and extractors and 2 1/2" exhaust went relly good,cam was a mild crow grind.
If you want to look at this head its been in my garage for 4 years with very low ks since being built. Call mike on 0425769790. Area narre warren.melb
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