SBC CHEVY 383 WISECO FORGED PISTONS 4.040 -7.5cc RD DISH 5.7 ROD KP482A4
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WISECO FORGED PISTONS 4.040 BORE SIZE FOR SBC 383 ENGINES, -7.5cc RD DISH TOP FOR USE WITH 5.7 BUSHED OR PRESS FIT RODS. .040 OVER.
Rings not included. The correct size rings used with these pistons is listed below in the piston spec chart. We offer the correct rings for these pistons in our other listings.
The Wiseco fully forged pistons are rated very high in the street/strip performance industry. They offer several price levels of pistons, starting with the Pro-Tru Street version made with 4032 forged alloy. The next level up would be the Pro-Tru series that are much more expensive and made from 2618 aircraft alloy.
Our custom made Wiseco pistons are very close in comparison to the premium series as they are made using the 2618 aircraft alloy.
Some engine builders use the non-forged hypereutectic pistons, and we find them to be very risky for any carbureted street rod engine. We would not even consider using such pistons. If the pistons are non-forged or forged 4032 alloy, they may fragment from the effects of detonation. This can then allow the connecting rod to destroy the block, crank, and cylinder head. Those types of pistons are fine for stock or very mild engine builds, but should never be used in carbureted engines built to high horse power levels. These type of pistons, especially the hypereutectic version, will not stand much detonation. The forged 2618 alloy piston is so much more resistant to the effects of detonation, and heat.
The -7.5cc RD dish piston is the perfect size dish piston for those running the very common 64cc combustion chamber heads on pump gas. The compression ratio this creates with a 64cc head is most desirable for just about any medium to serious build. We had these pistons custom made for those wanting their compression range in the 10.6-10.8 range. We find the compression ratio for flat top pistons to be a bit on the high side for a pump gas street rod when used with 64cc heads. Many people choose the flat top piston to obtain a decent quench/squish zone. What they don't realize is that our Wiseco dish pistons have the inverted/RD (reverse dome) design to them. You still get all the benefits of having a very good quench/squish without the unsafe amount of compression. We use the -7.5cc pistons in our most aggressive 383 engine. The compression range they produce is certainly in line with cams in the 560-600 lift range.
Our Wiseco Forged pistons are custom designed with an increase in compression height. This has many advantages. Here are a few facts about compression height and deck height.
Our custom made Wiseco pistons have a compression height that is .015 taller than nearly all catalog pistons on the market. We find this to be a very valuable feature. Since our pistons sit at a taller than normal compression height, you will only have to remove approx. .010 off the deck surface of a virgin block to achieve a zero deck. This also allows for future deck re-surfacing and still not ending too far below stock deck height.
Leaving the deck on your block thick makes for a stronger block that resists flexing and also runs cooler, as the deck thickness has a lot to do with the dissipation of heat. Blocks with decks cut down to any great amount are also prone to cracking. This is why our pistons are designed to sit flush, (zero deck) at .010 below stock deck height.
Since nearly all catalog pistons on the market sit .025 below the surface of a virgin block, the only way to achieve a zero deck using such pistons would be to cut .025 off the deck surface. This compromises the integrity of the block, in our opinion. Should you decide to leave the block deck higher up, using such pistons creates a new issue of having a very poor quench/squish zone. The only way you could really take advantage of a catalog piston is by having a block that needs to or has already been butchered down to 9.00 deck height. At that point, we don't think you should not use such a block. Having the piston sitting flush with the deck is very desirable, regardless of the fact that your overall compression ratio is slightly higher than if it were sitting below the deck.
We have found that 95% of our customers are using a virgin block or a block that is close to stock deck height. This is why we have designed our pistons to have a taller compression height. On very rare occasions, you may end up with a block that has the piston out of the hole by a few thousandths and this not a problem at all. Most head gaskets are approx. .040 thick, and should you end up with a quench zone of .035, then that is perfectly ok. If the quench zone ends up too far below .035, then there are plenty of .050 thick head gaskets on the market. One more benefit to this is that most machine shops charge much more to deck a block down from stock deck height to 9.00 than they would to do a light cleanup, and that's all that's needed when using our Wiseco pistons.
Another good feature about our pistons having a taller compression height is that the ring land above the top ring is much stronger by being .015 thicker. When pistons encounter the effects of detonation, it is not uncommon to see pistons with the ring land above the top ring broken off. The thicker ring land also makes a better heat sink.
You may have noticed that our Wiseco custom made forged pistons are referred to as Racing Pistons on the package. This does not mean that the pistons are for racing only. This is a generic term, referring to their ability to be used in high performance applications as well as for street rod use. These pistons are perfectly designed for use on the street, as well as for medium to upper level drag racing.
Our custom made Wiseco forged pistons are made from 2618 aircraft alloy. We find this alloy to be much more suitable for high performance engines than the common 4032 forged alloy. You will usually see the higher end pistons on the market using 2618 aircraft alloy.
Why go with 2618 forged pistons? If you encounter certain tuning issues, detonation is highly probable, and its effects can cause severe damage to your engine. The 2618 forged piston is able to withstand the damaging effects from detonation to a higher degree than the lower cost 4032 forged pistons, especially non-forged hypereutectic pistons such as Speed Pro or Keith Black, and many others.
Our Wiseco forged pistons will clear most any valve size on the market with ease even with the use of large lift cams.
We have built approximately 3500 engines using the Wiseco pistons. The engines have been for street rod and strip use. We have seen no problems, nor have there been any complaints. They are an excellent product in every respect.
These pistons are also suitable for use with nitrous systems up to approx. 250hp and superchargers up to approx. 15 to 17lb.s of boost. For the slight increase in cost, this is the best value on the market.
WISECO FULLY FORGED REVERSE DOME DISH TOP PISTONS RATED AT 700+ HP. THIS AUCTION IS FOR A FULL SET OF PISTONS. WISECO PISTONS ARE 100% MANUFACTURED IN THE USA. THEY ARE ONE OF THE HIGHEST RATED PISTONS IN THE COUNTRY.
These pistons are for use with full floating bushed rods, or press fit. The compression height is 1.440 2 valve reliefs. Ring groove size, 5/64 5/64 3/16. See full piston specs below.
We offer these pistons in flat or dish style as well as dome top, and most other bore sizes. See our other listings.
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