getrdunn

iTrader: (7)

i got all the valve train in and adjusted on my 496 rebuilds. they are mark 4 block and have dart pro 1 heads. the intakes i bought used and look perfect. one had never been bolted down and the other one had only been run very few hours. i just set them in place this evening before bolting them down and i noticed one of them had about a heavy 3/16" to a 1/4" gap on the front and rear between the intake and the block. the other intake end gaps appear fine with near 1/8" gap. either intake appears to have been cut. the both look like untouched factory finish on all surfaces and visually look great.

these measurements where with the AFR gaskets in place however not bolted down. i just set the gaskets in place and then set the intakes on to check alignment etc. any ideas as to why the one would be setting up so high. i was ready to call it a day anyway so i did not go any further and just thought i would check to see if anyone has any opinions on this. all angles / surfaces appear to be fine by the eye anyway. tomorrow i can start measuring however any help before i start would be great.

thanks,
john

cbellamore

its pretty common sometimes

if your block has been decked it will leave a gap in the intake manifold on the front and the rear,

also if the heads have been milled you will get the same result

either way you should get a good measurement and just have the intake milled down to fit the blocks,

or if you can bring the motors down to a machine shop and let them measure with good quality dial indicators (if you dont have any or are not comfortable taking the measurement)

shouldnt cost you much to have the intake milled down to fit,

I had to do it 1 time with a sbf Dart 351w block and a brand new edelbrock intake, with brand new AFR heads,
block or heads were never decked or milled
sometimes it happens
i'd be willing to be though especially with the age of MK IV blocks that they were decked at 1 time if they were ever rebuilt

even as little as .020" will require to mill the intake a little bit

FIXX

iTrader: (2)

did you try swaping intakes from engine to engine,part #'s match? the one thats off may be a tall deck intake.

getrdunn

iTrader: (7)

i have had them off a couple of times myself and just let the machine shop handle it. it was easy when i USE to live just a couple of miles from a speed shop. the heads are new and have not been milled and by the looks of the intakes they are untouched as well. it's ussually pretty easy to tell from looking at the surfaces if they have been milled. like you said it could just be that the block had been surfaced and is throwing the geomety a bit. i'll take a little closer look at it tomorrow.

thanks,
john

getrdunn

iTrader: (7)

they are both dart std. deck rectangular port intakes. my plan was to swap them tomorrow to assure that the problem is in the intake. if so i will have to send it off to a machine shop down state. i would imagine they will have to take about .015 to .020 off each side to lower it .030 to .040.

i do recall both blocks being surface and matched one another. so i would think that would be ruled out.

i would imagine the shop would want me to torque the intake down with the gaskets and then give them the measurement at the front and rear. i would assume they would be the same. if not i may have to run the whole engine down. i don't really want to do that though if i don't absolutely have to.

it never fails to have these type of things happen when you venture away from stock applications.

Young Performance

You ideally want to line up the intake ports of the manifold with the heads. Put the intake on with the gaskets and see how high the ports are. Then put the intake on without the gaskets and see where you are. The typical gasket is about .060. If it is on the money without the gaskets, then have them cut .060 off the intake. If it is too low, then cut a little less. You can judge by how far the intake moves when you remove the gaskets to give you an idea of how much needs to be cut. Don't worry about the gap at the china wall. It is what it is. Just worry about lining up the ports.
Eddie

Strip Poker 388

iTrader: (6)

I had to cut the china rail,the heads and block was cut apretty good bit

cbellamore

yeah I forgot to mention to make sure you line up the intake ports on the heads and the manifold and trim according to that,

you should be able to see down the intake runner on the dart single plane intakes so it makes it a bit easier to line up