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12 Posts
Sorry to revive an old thread, but I'm wondering what would happen if you just changed up the firing order to 1-6-2-4-3-5 and roll with the stock series 1 cam just slightly modifying the LSA to work?

Obviously you'd have some uneveness having 2-4 and 3-5 being on the same banks, but it should still be even firing if my understanding is correct.

If the engine could withstand the vibrations, it would sound like a sbc.

Not sure. Still figuring out engine dynamics!

9 Posts
Coolant bosses from the block into the heads isnt a big deal... at least the SII isnt reverse flow and have differences like a reg sbc vs LT1/LS1

the valves arangment is different ie. the cam lobe timing events are tailered for the I-E-I-E-I-E valve positions of the SII and not the E-I-I-E-I-E of the LN3, this is one of the only things that I have found different between the cams (besides the sleeve bearings that got changed from roller bearings on the balance shaft, and I dont think that the balance shaft bearings changed anything with the cam bearings).
like I said we will be doing some research in a Jyard and comparing/measuring parts
Lowbuck redneck hotrodding lol
I am still planning on some stuff fer the 3800 when the turbo goes on, if the cam differences turn out to be more than a lathe and bridgport can work with, then Oh well but you never know till you try I am still determined to use the S I supercharged heads with their own inj ports and the NA (Series I) lwer intake with it's own inj ports, 12 inj will be possible and with MS EFI tunable....the rest is easy lol
a new fabricated uper intake with a TB (N* or Ls1 etc) located at an angle would improve IC plumbing....

the SII head gaskets would have to go with the SII heads on the SI block from the looks of em, I can compare the gaskets and see which works best with the block/heads

OK so there is no problem swapping the heads/intake from a SII onto a SI LN3 block, there will be spacers required for the intake (LN3 tall deck block). the 12 injector setup would be possible, the exhaust manifolds are no problem since Xover has to be modded for the turbo
the main hurdle is what are the differences between the SI cam and the SII cam on the cam journal sizes, and how it bolts to the cam gear
both are hyd roller cams and the blocks have the exact same lifter bore spacing

just need to find out fer sure on the SII cam if I can mod it to fit into the SI block
H*** the cams could be identical but with a different bolt/pin setup for the cam gear, in which cas a LN3 T cain set and a SII chain set will fix that problem lol

the SII heads have larger valves (that I can backcut and do 5 angle seat work on (I have a valve seat grinding machine) the SII heads will flow more than the SI and fully ported SI and SII heads will be that much better than the stock castings. pic of SII NA and SC heads....dont have any good shots of SI heads....

I already have all the neccesary tolls for porting and polishing, and have done full port/bowl/chamber work, backcut valves, ported intake and exhaust on the 90 LN3 3800 we installed into the rear of the 94 Olds Cutlass 442, the same mods have also been done to the 3100 V6 in the front engine bay.
being different is part of the goal but more power for cheap is the main goal, after all with a unique car like our twin engine 94 Olds 442 needs some unique V6's! we are looking to have twin 3800's in the front and the rear of the 442 and have both of them Turbocharged/IC if we can get 350 Hp from each 3800 thats 700 Hp with AWD! YEEEHHAAWWWW!

Here are some more pics for this thread...borrowed some photo's and have been talking with a few Holden guys from downunder and evidently the swap hasnt been tried/accomplished but people have talked about it but i guess no one got off their duffers and tried it, or at least went to a Jyard to do some testing/measuring lol.

and here are some pics of the SI and SII cams (the two on the right are the SII) and they seem to have the same length and lobe/journal spacing (the pics of each cam are from different positions) just with different lobe phasing, and maybe a different thread on the cam gear bolt, but the snouts look identical!

I am still reasearching this on the web but when I go to the Jyard we will know fer sure and I will be able to take measurements/dimentions of all the parts involved.

blazing new trails, REDNECK style! James
Hay buddy think u can answer a question of mine. In what order do the cam lobes run on the camshaft. Is it x i i x & so on? Or is it i x x i ? I know the heads r marked but im a bit confussed on the lobes. Car is a series 2 l67 3800.
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