Thread: Vortec heads on MKIV

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Hi! Newbe here, I didn't have much luck with your search so either I asked the wrong thing or you don't think much about them. I was just wondering that's all. Building a 489 with KB Flat Top Hypereutectics for torque and was wondering if I should go with the vortecs of a set of 049's. Thanks a bunch!

The vortecs will make more torque in the low revs and be pretty close to any other head ,untill about .500 lift and 5,000 rpm after that the after markett alu. heads are better.This is sb,I do not know the specs on the bb heads,I am sure they are in line with the sb head.

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I got around to checking the 049's , the guy told me they were 113cc and I see there 120cc+. Good thing I didn't take the time to go look at them. So I bought the L29's. The threads I have found are promising but I would like as much information as I can get on these. I'm going to use this 489 on a Direct drive Airboat so torque is the key as the thing won't be turning over 3200 RPM. Any info and tips you might share sure would be appreciated. Thanks!

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Yeah! He could probably climb mount everest with that one!

You will want to read as much as possible on increasing low lift flow and torque,before touchin those heads,vavles ,bowl work,porting,all have specific procedures for low rpms and torque,rather than high hp ,high rpm ,engines.A little info before hand can pay off big time with those heads.As far as the cam goes ,thats a little tricky.3000 ,3500 rpm red line,will need a specific cam if you want to get all the torque possible from the parts you have.I would talk to a cam company or a place that specifically deals in those types of engines(almost always this is free).I have no exsperiance with those engines,but I would imagine that the cam will be 1 of the key components in that engine.The vortecs flow just off the valve seat,what other heads flow.100 lift.The head in stock form slows down at higher lifts and becomes less efficient,but that is ok ,the valve is only at full lift 1 time in the cycle,buy its at low lift 2 times each cycle.If it was me I would not port or bowl work these heads at all!!!All the numbers at low valve lifts(which happens 2 times each cycle) fall off,while the high lift (which only happens 1 time each cycle) go up.IMO you will not be working these heads very hard at all at 3500 rpm(a head runs outa air at higher rpms ,not low)the only increase in air demand will be the cubic inches of the engine.Soo at 3500 rpm and a larger displacement ,the head will only see a (percieved) rpm of 4000 to 4500,right at the rpm these heads start to nose over at and stop making power.That means you are getting the full power potential (not flow potential)of these heads at stock form.I would spend my money on a good low lift type seat in the head(cheap to do) and on a good low lift flow type valve job to help increase the flow at lower lifts,which equals more power where you need it.I would read as much information as I could to help me understand how that setup works.The high flow rates at high valve lifts at high rpm looks impressive and so do the hp numbers to back em up,but that all takes place at 6000 rpms or more ,well above the actual requirements of your engine .You can see where it would be easy to get a set of big aftermarkett heads with huge flow numbers at huge lifts and rpms and end up with a motor that barely runs........Just tryin to help make more informed decisions,I hate to see time and enthusiasm wasted for lack of almost free information..

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There you go ,Pat knows how to do what I am taking about.I understand what needs to be done ,and why,I just do not know how to do it!!! Your job as a engine (customer) is to give the engine (builder) the application specifics so that the( builder,some one like pat) can do what needs to be done to make it happen.You can see how 1 little piece of info ,like only turning 3000 rpm or the fact its going in a air boat changes everything.Comunication is a major key to sucess in anything!!!You need to have all the facts and not "hope" it all turns out well.The engine will only turn out as good as the information you provide the builder!!!!

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Was just checking the waters, I like free information so I had to give you a bit more. I have some peanuts but i would have had to epoxy the intake for a nice port match. I think lots of extra advantages by going to the Vortecs, so I ordered them! Keith Black recommends polishing the combustion chamber, exhaust port and valves so I will do that. He also recommends a .040" quench but I wont be turning 6000RPM so that might get tighter. Everything I have read suggests like a ribbed finish on parts of the intake to promote a boundary layer and with that wing turbulence should be great and fuel drop out not a problem.

My initial post was my concern as to if they would bolt up to a MkIV and after reading enough I see that part isn't a problem, however I am still wondering if steam holes have to be drilled, coolant passages ground out, heads can be tapped for MkIV rocker studs or do I have to buy the conversion ones. I'll be able to answer some of that when the heads get here but i figure you guys might have experience!

So! So far I have 454 cid MkIV block, 4.25" stroke crank, 6.385 rods, KB Hypereutectic +.030" flat tops +3cc, L29 Vortec heads 99cc, Dual plane intake, 600CFM Holley double pumper, Long tube small diameter headers, HEI, MSD, I'll talk to a cam company for a cam, I was told I want a 108 degree lobe separation so the cam will be peaky between idle and 3200 RPM.

Exhaust system to augment torque, X pipe or 2 X 2 1/2" inlet and 3 1/2" outlet might work.

I really appreciate your help guys, I don't get to work on the fun stuff often enough!

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Thank's for the info. I already have guide plates and studs off the peanuts and a friend with a machine shop, right on! I'll just Zero Deck the block so quench will be the head gasket thickness, like .038". 6 degree lobe seperation on the cam. Great resource!

Oh Yeah! I was thinking 0.002" cyl to wall but wondering if I need another 0.0005". Never built a Hypereutectic before!

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