The engine in my Z is dying slowly (lotsa blowby). I acquired a new block and have the money to build it. Many people tell me to build a 350 or a 355 but I'd like to do a 383. A 383 would probably be more expensive since the block requires notching, maybe a small base circle cam and .030 over pistons. Should I stick to a 355 or build a 383 ? I have a TPI, the ability to burn my own chip and plan on buying a better cam for more power.

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1991 Z28

 

If you really want some good performance go with the 383. Whether you go 355 or 383 you will need .030 over pistons. Also you can do the block clearancing yourself with a simple hand grinder. If you decide to go 383 let me know and I'll give you some tips to avoid the problems I ran into.

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Riccioli Performance Motorworks

--RPM Racing--

Getting there.....383 with Super Ram, Bosch 24# SVO's, MSD, Edelbrock 58 mm TB, 700R4 tranny, Eibach springs, Koni 12 way adjustable shocks and struts, and more!! Now let's pray it runs when it's all back together!!!!

 

That's what I'm leaing towards... a 383. I would guess this notching would have to be done after the machine shop work as not to get all of metal chips everywhere inside the block. What else "special" would I have to do beside getting a 3.75 throw crank ?

 

If it's possible I would actually notch the block before your machine work. Get your crank and rods. Install your crank and just slip the rod into each cylinder without a piston and see where you will have clearance issues. It would be best if you had rod bolts in the rod too. I had my rod bolts cut because I was going to have real issues in some of the cylinders. As far as other special parts you may or may not have to get a low base cam....I didn't. You may also have to slightly notch your oil pan which you can do at the end. Oh yeah one other thing that I forgot that I went crazy with. When you get your crank make sure you ask whether or not you need to use chamferred rod bearings because if you need them and try using standard ones your rotating assembly will bind up on you.

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Riccioli Performance Motorworks

--RPM Racing--

Getting there.....383 with Super Ram, Bosch 24# SVO's, MSD, Edelbrock 58 mm TB, 700R4 tranny, Eibach springs, Koni 12 way adjustable shocks and struts, and more!! Now let's pray it runs when it's all back together!!!!

 

I did a 388 buildup with the eagle kit, and the only clearencing I needed was the back counterweight, the even bank of cylinder bores cleared, but a piece of paper had light drag between the bore bottoms and rod nuts, so I took a little off there. One place it definatly hit was the top of the #2 rod hit the cam. With a grinder I just knocked the edge off the rod top and bolt. #6 was too close for comfort so I did the same although it cleared, I figured the chain could stretch and maybe under some instance it may touch....

Other than that no probs.... I did all the clearencing after machining and cleaning by 'masking' off the area with plastic and tape and placing a magnet near where I'm grinding.... All the chips and dust went right to it which made it not too bad to wipe out.

 

Crucial, go for the 383. I cannot be considered an engine builder but let me relate my experience as a first timer.

I am, today, going through the second phase of break-in on my 383 (Saweeet). Cam has gone through break-in and am now trying to get some easy miles on the road. Tomorrow I'll be making some mild acceleration runs. I'm impressed, so far. It wants to rip.

Getting back to the beginning, I presume that you are starting with an L98 block, which I have no experience with.

Mine was an older 3970010 4-bolt main that required considerable stock removal in the area of the pan rail and some at the bottom of the cylinders. In the area of the pan rail, on my block, I was flirting with the water jacket (big-time and I've got the first block sitting in my garage all machined to prove it).

If I were to do it again, as I did my second time around, I wouldn't put a dime into the block until the clearancing was complete, although I did have it hot-tanked first.

While you have your grinder out you might want to clean up some of the casting flash and sharp edges and smooth out the oil drain ports.

Treat that grinder with respect.LOL.

 

If your starting from stratch anyway, go with the 383. They make a lot of low-end torque, and still pull hard on top. I have built 4 of them now, (1) truck engine, and (3) HP Street/Strip versions. The one in my 82 Z28 has been the nicest, in terms on aftermarket parts such as the block, heads, rotating assembly, but even the 2 I have built with stock heads, rods, etc have been very impressive.

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82 Z28 383, Ported 215cc Dart Iron Eagle Heads 72 cc Comb. Chambers, Comp custom grind Hyd roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 830 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET:11.60 @ 114.56, w/ a 7.34 1/8 @ 93.50, and a 1.622 60'


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock

Bassett Racing

 

Changa2 I feel your pain on that water jacket issue. I did the same thing on my first block. That's why I decided to have the rod bolts shortened on the second block....what a difference!!!

 

If you only grind on ONE of the rod bolts, doesn't that throw it off balance considerably ? I'd figure if you're gonna grind em, you better grind all of them, or get it rebalanced afterwards. So Paul, you think I should have the rod bolts shortened then ? Does that still require clearancing of the block, or not as much anymore ?

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1991 Z28

 

You will still have to do some clearancing for the crank counterweights probably. Cutting the rod bolts will reduce your grinding by a lot, but you still may have to clearance a little for the bolts. Try to do all your grinding before you have your machine work done. Have your assembly balanced while your block is being machined.

 

I'm looking at car craft's TPI 355 450HP build up. They used a miniram, gm fastburn heads and a TPIS ZZ409 camshaft as main "ingredients". I already bought new trick flow heads and I have a high flowing TPI system. IF I get this cam and keep it a 355, I believe I could be pretty close to the 400 HP mark at least. What do you guys think ?

p.s. even have compcams custom grind me a cam to those specs. 226 duration intake/exhaust and 560 lift on intake/exhaust

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1991 Z28