[rocam69]

Hi guys,
I am in the process of a street engine build and i am undecided between a 350 bored .060 over or going with a 383. My top end (which is already bought) is a edelbrock 2098 kit it is rated at 410 hp on a stock 350 bottom end (the heads are a 64cc chamber with 185 runner 2.02/160. I guess my question to you is has anyone on this forum used this kit on a 383? from the reading I have done I am under the impression that the compression will be way to high for pump gas (like 10:7:1), but if that is right why does the 383 kit (from edelbrock) have 64cc heads and a 9:5:1 compression?.
Thanks.

 

[vinniekq2]

A 410 HP 350 will also be about 410HP 383,just at a lower RPM.The torque might be a little higher in the 383.The lower RPM is good for most people.What do you like or want?

 

[my87Z]

Okay, I was trying to look up this part EDL-2098 top end kit. I ran into a bit of a problem. On Summit Racing they have the kit with 170cc intake runners (not sure if this is a typo on their part) or if they are selling the performer rpm E-tec heads with this combo cause the E-tec heads are 170cc and I believe that they are a vortec style head. Then I go to Edelbrock.com and do a search for the EDL-2098 kit and it comes up with the standard Performer RPM heads that have 185cc, and the 234/244°, .488/.510" cam with it. If I where you I would look into exactly which heads you have.

If you have the 170cc E-tec heads then I would build the 350. I think those runners may be a bit on the small side for a 383 with a cam that will spin it to around 5800-6000rpm. It would still work and make good tq but wouldn't make as much hp. But on a 350 those heads would be just about right.

Now if those heads are the 185cc RPM heads then I would certainly build the 383. I've built 3 different 383's and I really enjoy that motor. IMHO they are the perfect engine for a street machine. Vinniekq2 was pretty close to right on what you can expect to see out of a 350 vs 383, but I would say you could expect to see about 3-4%hp gain from the 383 which at your level is only going to be around 10-15hp. It will get into the power curve about 500rpm ealier than the 350 and it will peak out at about 500rpm ealier as well. Now where you will see the most improvement is in the tq side. You could expect to see about a 7-8%tq gain from the 383 which in your case should be around 30-35tq.

Now for your question about the compression: this will really all depend on what pistons you use. you mention a stock 350 bottom end (but yet you also mention it having to go .060" overbore), this could be anything from old flat tops to the garbage 22cc O dished pistons. Here is what i would strongly suggest: first make sure that the block can handle going .060" over, if this is stock bore block, then you only want to bore it as much is needed to get the cyl walls smooth and clean, don't go to .060 just becaue it will add 10cubes to the displacement :nono:. Then if the block will handle what ever bore, align hone, deck... then have that done, then go buy this kit

Eagle Specialty Products B13004E030 - Eagle Street and Strip Rotating Assemblies - Overview - SummitRacing.com

Or one very similar to match your over bore size that you needed to go. these kits typically come with the rods already clearance so very minimal work should have be done. i've used one before and they work just fine with a stardard base circle cam, but i did have to clearance the the pan rails just a tiny bit and i also have to clearance the bottom side of the cylinders just a tiny bit. if you dont feel comfortable doing this than a machine shop wont charge very much ($100-150.00) to do it. this kit uses the 18cc KB hyper pistons (which is exactly a set that i used to have) that with the 64cc combustion chambers will put your compression at 9.5-9.6:1.

that kit on a 383, with 9.6:1 compression should make around 420hp/440tq. The added tq, and the lower rpm band is well worth the few extra hundred dollars you will spend building the 383 when it comes to driving it on the street.

 

[BogiesAnnex1]

Hi guys,
I am in the process of a street engine build and i am undecided between a 350 bored .060 over or going with a 383. My top end (which is already bought) is a edelbrock 2098 kit it is rated at 410 hp on a stock 350 bottom end (the heads are a 64cc chamber with 185 runner 2.02/160. I guess my question to you is has anyone on this forum used this kit on a 383? from the reading I have done I am under the impression that the compression will be way to high for pump gas (like 10:7:1), but if that is right why does the 383 kit (from edelbrock) have 64cc heads and a 9:5:1 compression?.
Thanks.

vinniekq2 hits it pretty well, these heads have ports that are a bit small for a 383 and the cam timing will be a bit short as well. What will happen is that the horsepower peak will remain about the same and might drop its peak some RPM. The torque curve through the mid revs will be fatter than the 350 as at these lower speeds the ports can feed the engine size. The peak torque will come in at a higher RPM and closer to the peak horsepower RPM. All-in-all this will be a damn good grunt motor with a sufficient top end for anything but out and out racing.

Compression will be a problem with the 64 cc chamber, the solution to getting that where you need it is the D dish piston. The advantage of the D dish over the circular dish is that there is a flat area opposite the valve pocket that acts like a flat top in the sense that it maintains a very effective squish/quench zone that builds a lot of mechanical octane and high fuel burn efficiency into the combustion chamber. The Keith Black on line catalog has many selections of this type piston for the Chevy in both hypereutectic castings and forgings. There are many other brands as well. So check 'em out. Black has a great compression calculator for both static and dynamic ratios that are easy to use with a few pieces of data from your build, like where the intake valve closes in crank degrees and rod length as well as the volumes of the cylinder sweep, combustion chamber, piston to deck clearance volume, and gasket volume. A note, you want to get the piston to squish/quench pad of the head clearance to as close to .040 inch for a street motor. For a race motor you can go closer by accepting the risk of banging the piston into the head, a price to be paid to grasp the brass ring at the track; not something the usual street driven pick up needs.

Bogie

 

[dirtburner]

or????

Another good choice may be to just build a 400 shortblock. If your object is street use and not high rpm, a 400 is always a good but overlooked choice. Dont be scared of a 400 as a street engine. just be sure u drill the steam holes in your heads. with the short rod, big displacement they are a monster off idle. and aftermarket parts from scat, ross, eagle, ect. are readily available. I dont wanna sound like a broken record on my posts but, check with some local dirt track guys. alot of them used to run 406's and have switched to smaller spec motors to avoid claim rules, and run higher rpms. you may be suprised at whats out there. I just picked up a full roller 406 with bowtie heads from a guy that went to a 355 for 1100 bucks complete. racingjunk.com and dirt forums are a good place to start if you dont know anyone. Lately I personally have been picking up complete cars cheap. as far as a street rod or street car build they have lots of useable stuff, ie: floater rears, engines, tripledisc clutches in some cases, spendy gauges, wilwood brake stuff, pedal assemblies, fuel cells, and usually some other trick stuff. worth a shot.

 

[my87Z]

400's do make for a good motor, I dont care for the 5.565" rods though, if i where to build one it would either have 5.7 or preferably 6.0" rods in it. the real issue with 400's is first off trying to find one, then on top of that, finding one that can be cleaned up while still keeping the walls thick enough as not to burn up. for a 400 now a days it's almost worth it to go with an aftermarket block, and then if you are spending that much money why not build one with a 3.800, 3.875, or 4.000" crank and make a stroker.

 

[dirtburner]

nobody ever said the addiction we have is cheap, hahaha. I frequently start things on one budget and throw the budget out the window shortly after the project starts. Gets harder and harder every day to explain things to my wife like " but hunny , now that i lifted my truck 3 more inches the other tires look too small so we will have to buy new ones"

 

[rocam69]

wow, alot to consider thanks for all your posts guys.

 

[bentwings]

A low comp 350 RPM motor makes a fine blower motor. idles smooth at 750 in gear, all the power you can use on the street and then some, and with a lot of tweeking you can get pretty good mpg.

20k miles on mine.