Boingk

Bingo. And there's no use having eleventy billion horsepower if it all comes in at once at 8,000rpm. You want area under the curve as slydog says above. I'd take a nicely set up mild 400-500hp street engine any day over a peaky 800-1000hp unit. If you can put your foot down and get a wall of instant torque shunting you forward you will shit all over the guy with a peaky engine who has to shift, spool up/rev up and finally start launching.

Thanks mate, confirms what I was thinking all along. I'll be running 3.50's in the rear with M/T ET Streets so should go okay there with everything else similar. I've read up big time on the cylinder head so should be good for a home port job now I know where the gains and danger spots are. More than happy to mate. One of the reasons I like keeping score is so I know what I need to sell the car for if/when that time comes, as well as what to resell a part for. Hmmm, did that intake cost me $50, or was it $250? Mightn't make an earth-shattering difference at the time but it all ads up. Seen mates do that, never understood it. Best money for me is always spent on ignition, intake and valvetrain. Exhaust comes a very close fourth. The air pump analogy is always a good one here. I'm hoping with a goal in mind the plan isn't too hard to nut out right the first time, but we'll see where I am inn a few months I suppose. Anywho, onto the build thread - I picked up a ute the other day. I'll make a dedicated build thread in short order.

Look at the engine you are building and decide on the most cost effective way. There will be positives and negatives each way. For a given engine, example a 250 crossflow, a zero-decked flat top might give you too much compression with even a stock head, but a stock piston will give you only average compression with a stock head. If you want something in the middle a mild dish and machined head may be the way to go. There is some evidence floating around that a mild dish helps centre the force of the combustion and helps with initial squish and also pre-ignition. This passes the common sense test in that you will get some good charge distribution from the narrow sides forcing charge into the centre as the piston rises, and have a friendlier shaped combustion chamber floor with regard to pre-ignition. The shape of a chamber is more important than the volume, but there is a limit where a good shape and unshrouded valves of appropriate sizes can all co-exist. Generally this is a nice semi-hemispherical chamber with rounded, smoothed contours focussing on the valves edges. Short answer? See what is reasonably available for your engine and go from there.

Thanks mate, duly noted. I'm starting to think a bit more that way but again I'm also not looking to run 10's or even 11's. Mid 12's would be plenty for me - enough to have a play at the track with some V8 gear and not look shamefully slow. Low 12's would be a bonus but I expect the engine won't be the only thing holding me back by that point. Good reading, cheers for the link mate. Nice ride! Nah not much. Cheap ute, an engine to build while I drive it and sort the gremlins, and a whole lot of elbow grease by yours truely. I'm not a mechanic by trade but have tackled most jobs so far by myself. This is why I'm starting a year out - the magic triangle: Lotsa time / Lotsa money / Lotsa effort. Pick two and you may not need the other! Cost list so far: $1000 - ute with reco 250 / 4spd / HD clutch / lotsa rims $250 - donor XF - motor, radiator, spare trans / housing / flywheel etc $240 - set of sunraysias in 15x7 $100 - new tonneau cover $100 - basic service (coolant/filters/oil/plugs) $50 - new tail lights $50 - new hardline for fuel system $100 - new fuel pump $600 - Aussiespeed manifold $600 - NX Mainline nitrous kit including plate, AN4 line, etc ------------ $3090 total so far Budget about a grand for the camshaft, rockers and pushrods, another 200 in machining the head, 700 in M/T ET Street's, 150 for new diff gears and all I've got left is the carby... which I probably already have. Call it about another 1200 and I'm set. So whats that 4290 bucks? Not nothing but certainly far from big bucks, only thing missing is a decent ignition. If you have a place to work, some basic tools and a phone with the 'net you can get any job done. - boingk

Fair call. With adjustable rockers solid lifters become just a quick purchase away... Looking at two choices here from Camtech: CT142-609: i231/e235@.050" / i496/e500 lift / 2200~6200rpm / min 9.5:1 compression CT142-608: i241/e243@.050" / i522/e522 lift / 2500~6500rpm / min 10:1 compression The top choice looks like it'd be great for everyday use which is 95% of what I'll be doing, and the bottom one would be a hoot for a more dedicated machine. They are the smallest in the range but that's fine by me as, like I said, this will mainly be a street-driven, full-rego type car with only occasional strip time. Anyone have experiences with those? And yeah looks like ACL is down and out. Bugger.

Thanks mate, solid lead there. 1.75" would be nice, the things I have at the moment look very spindly (press bent 1.5"?) and were bought for a mild hop-up with another vehicle. ACL do pistons according to their website: http://www.aclperformance.com.au/EU/6MKRY9412.htm With the dished set at .020 over, a 50cc chamber, .030" deck height and .040" head gasket at 3.7" bore diameter it all comes to about a 10.8:1 compression ratio by my calculations. That should be plenty for what I want to achieve and still use pump fuel. I also stumbled on some bolt-in style roller rockers which look interesting, they use a 5/16 stud that goes into the head which then enlarges to a 7/16 stud for the rockers themselves. Anyone have any experience with this type of setup? I know its not a proper full 7/16 stud but then again I'm not running a top-spec full-tilt camshaft either. - boingk

Thanks mate, much appreciated. I'll look more toward that direction then, if the valve gear won't hold I won't try and make it. I'm more used to Chrysler V8's and their great shaft-mount system and I keep forgetting how different stud type rockers are in terms of reliability at speed and load. Weight-wise, the ute is going to be pretty standard. I'll probably try and pull a few tricks (single sheet bonnet and tailgate, light tonneau cover for aero) but otherwise will be fairly limited as I want it to be usable as an everyday ride. Decent exhaust isn't an issue, big single 3" dumped out the back. Headers will be a struggle as off-the-shelf items don't have the primary size I'm after, at least not the one's I've seen so far. Ignition I'm leaning towards a 6AL style box or an ICE ignition module. I've had decent experiences with them so will see what I can get within my budget. Narrowing down the options for the final Ute body at the moment, I'll start a thread once I've got it. - boingk

Thanks mate, well into it but not doing anything near that hectic. Pretty sure he's campaigned an XF ute in Drag Challenge for a few years now, too. I'm running an XF ute as well, nothing fancy at all and pretty rough at the moment. Cutting and patching panels type of rough. Looking to eventually run mid 12's, nothing fancy. Want to stay hydraulic flat-tappet for the camshaft to make thing easy, but what I'm looking at will be into the territory of a baby mechanical flat-tappet by most grinders catalogues. - boingk

Hi mate, I've seen this drawing as well. The sectional drawing reveals a very thin lower intake wall on the short-side radius and runner, so be careful if porting anywhere there. I would limit to a quick swiffer to remove casting defects. What you would be better doing is concentrating your efforts to the outside / top of the runner as it will help with the gently curved profile of the runner in encouraging flow numbers. From a peak of about 180-ish cfm you should end up with 200 to 210cfm is you do a decent job. - boingk