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Old 03-25-2019, 08:50 AM
BogiesAnnex1 BogiesAnnex1 is online now
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Quote:
Originally Posted by Cutlass92 View Post
Hmmm quite a few options too choose from thatís good too know. Iím honestly more leanient towards keeping my rims but Iím still undecided as itís the last on my list after everything else is done so Iíll weigh my options on that. I also wanted to mention that Iím fairly handy with cars Iím not a master mechanic but I do know a thing or two. Would the head swap and everything be something thatís not extremely difficult or would it be something that I should let a professional do. If so is that something thatís usually pricey to get done. I have an estimate from someone I just want to get some opinions to see if itís too high or too low
Head swaps are not difficult but are tedious with a lot of bolts, cleaning, keeping trash and coolant out of the engine, and keeping where the parts came from straight. You need standard tools and a 1/2 inch drive torque wrench.

Drain the coolant and disassemble carefully to minimize how much gets inside the moving parts, obviously an oil and filter change will be part of this. Keep the components of the valve train in order especially the lifters/tappets with the lobe they ran on this is critical if not one lobe and lifter have a very high chance of being wiped out. Also, a good idea to keep push rods and rockers matched as well but while important isn't critical like lifters to their mated cam lobe. Plastic organizers are available for this or you can devise something from cardboard to freezer bags for sets of parts with markings where they mate to.

GM heads can reuse rockers and push rods, aftermarket iron also. Typically aftermarket aluminum heads position the spring perch .1 inch higher from the chamber roof to make room for a taller port and accommodate thicker metal thickness cross sections, this sometimes happens on aftermarket iron heads as well. So these in addition to usually using a 2.02 intake and 1.6 exhaust valve instead of the factory 1.94 and 1.55 valve set, the aftermarket heads often use a .1 inch longer stem. So you need not only the proper valve in head diameter but also longer stem. The installed spring height and retainer with locks remains as GM for 11/32 stems, you have to watch for heads using 8mm stems as these take metric retainers and locks so the spring retainers and locks have to match the spring diameter and the valve stem diameter. Not difficult as it sounds just read the part descriptions and keep them in order by sizes or buy complete populated heads.

Those heads that use a .1 inch longer stem will also require a .1 inch longer push rod. If you keep the cam and rockers you have you need to know the push rod length in there now then add .1 inch. If your making cam and or rocker changes you will have to go through the push rod length drill (tour the web for details and videos) to select a length proper to the stated needs in these information sources. Keep in mind that nominally Chevy SBC with flat tappet lifters use a push rod of 7.8 inches length, the factory roller lifters use one of 7.2 inches.

Depending on rocker type that being self guiding or not self guiding the push rod material treatment can be different, where self guiding rockers are used the push rod can be unhardened or hardened it doesn't matter, however, for a not self guiding rocker the guiding function becomes guide plates or cast slots rubbing on the push rod which requires a hardened push rod.

Head gasket thickness will contribute to compression ratio and squish/quench clearance. A lot of aluminum head sellers use a thick .053 gasket, these lower compression ratios and increase the squish quench clearance neither of which is desireable. There are .028 composite gaskets out there which combined with the SBC piston being typically .025 in the bore at TDC is a lot better for compression and offers a better squish/quench at .053 instead of .078. FelPro sells a polymer coated .015 shim gasket that nets out at the magic .040 clearance for best squish/quench effect and preserves the compression ratio. Shim gaskets require the decks be in great condition, the composition gaskets tolerate more deviation from straight and smooth surfaces. There are a lot of online compression calculators to help you through these calculation as well as us here.

Bogie
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