I was wondering about the pistons... I know they are forged speed pro, but what size rod do they accept, and how much of an RPM will they take. They are press fit as well. I want to run a GM 847 camshaft, with 1.6RR's with a stock crank and eagle rods, but I am not sure which rods to order? I don't know if I will have to use 5.7", but since I am staying N/A I would rather have 6" rods? But either way I am happy with the kit. I am about to buy a 93 LT1 block, and my car is a 1996. When I build the engine, and go to put it in the car, do I have to use an unvented opti... well basically, what do I have to do while I am building it up to get it 96 compliant? I see that several people who purchased this rebuild kit ran the 847 cam and nitrous, but I do not what RPM they shifted at? I want to shift at around 6500-6800? Will it be possible, the rods (eagle, around 300 dollars) are rated upto 7,000 rpm's and 500hp, and seems no one has had a problem with them. This car will not ever see a power adder, as I would like to keep it N/A. Would the pistons become to much of a deterrant to shift at that RPM? Thanks for any help/suggestions.

-Eric

 

On their web site, I believe its for 5.7 rods..... Just give them a call about the kit and what you have in mind and they can make adjustments, usually......

 

5.7 or 5.85 would be fine if youre staying n/a

 

I got some brand new in the box 5.7 eagle Hbeam rods for sale, but there for floating pistons. that might be an upgrade option at summit. Im pretty positive the hbeam rods arent made for press fit pistons at all. Ive seen the Ibeam rods for under $200 new w/good 7:16" cap screws. thats what I would get if your never goin to use a power adder. they DO have those for pressfit pistons. you want to use the lightest poss. rods/pistons and Im pretty sure the speed pro's are heavy comparitivly (SP?). also the speedpro pistons might be made for the standard thickness rings. you should use the thinner/lighter piston rings to save rotating weight and friction losses. thats the goal for a high rpm engine.
chris

 

You can convert a 93 to vented opti fairly easily. I don't know the procedure, but it's been done before. With a 847 cam, you'll be best off shifting at 6800 or just below 7000. It's a big cam and needs rpms to work its magic. You should be fine with those rods you have. The main thing is to have good rod bolts like ARP's and keep the thing in tune. It wouldn't be a bad idea though to convert the block over to 4 bolt mains and use some Milodon caps for an extra measure of durability.

Jason

 

I used the summit rebuild kit in the 93Z that I just did, it's a good kit, just don't use the high volume oil pump that comes with it unless you get an aftermarket oil pan. The pistons are for a 5.7 rod. I don't think I have ever seen anyone spin a 847 cam to 6800, that's ridiculous. First of all the cam doesn't make power that high, and two I don't see the point in spinning the engine that high, it's a 5.7 liter not a VTECH. If do you want to spin it that high, obviously it will need to be balanced and you should go with a light set of pistons, (yes the speed pro's are heavy) good crank, rods, etc. Another thing is you will have to have a set of heads that will flow a lot of air if you want to spin the engine that high.
You can convert a 93 to vented opti, I ordered the parts from Jason Cromer, it came with a vented opti, new harness which you have to modify and vacuum vent lines. I went with the vented because we used a double roller timing set and an electric water pump. But you shouldn't have to convert it if you use your 96 stuff.

If you engine is a 96 is has OBD2 and has a crank sensor unlike a 93. As far as I know the actual blocks are the same(please someone correct me if I am wrong)however the crank hub is different because on the 96 because of the crank sensor. I would think that you would want to swap everything from your existing 96 over to the 93 block.

 

From everyone I have heard from, in my previous posts about the 847 cam, is that it loves to rev, and makes power deep in the 6,000rpms. Altjar shifted at 6800 or 6700 on the stock bottom end/ stock unported heads, and he said he pulls all the way through. From all of my understanding, its a high RPM camshaft, and everything I have seen (videos of 847 cars) they shift in the upper 6,000's and they pull hard. http://home.cinci.rr.com/atljar/atlj...Heads%20NA.jpg thats altjars dyno graph... tell me that cam doesnt make power above 6,000 rpms. I think that I am just going to use the engine in my car, and take that apart and do it with the downtime factor. I don't want to rush things, this is going to be my first engine disassembly/reassembly. I am fairly sure that I will be going with the Speed Pro/Summit rebuild kit, the eagle rods, (ESP-5700bplw) k-motion valvetrain, pace setter long tubes/y-pipe, stock crank (machined of course) and what not, i have a list upstairs somewhere. Oh.. and by the way.. its spelled
V-TEC !!!! theres no H

-Eric

 

I didn't know the 847 cam revved that high. and you are right, there's no H.

 

I used the Summit rebuild kit with forged pistons when I did my rebuild and everything went smoothly. One think you absolutely must do is get the assembly balanced. The forged pistons are MUCH heavier than the "lightweight" stockers. It's only about $200 for a top-notch balancing job. If you aren't planning to spray then get the Hypo pistons and make sure you get them balanced as well.