Right now I have an 84 Z28, L69, T5 and 3.73 posi.

I've added a few "safe" bolt ons but have been cautious in spending large amounts of money on a 305 b/c I wasn't sure I was gonna keep it.

I've decided to build up a 355.

I'm gonna start with an L98 block.
Rebuild, stock bottom end (if I can get away with it), forged flat top pistons.
I'll try to be around 9.5:1 compression.
A set of heads, 2.02 intake 1.90 exhaust 200cc

Comp Cams XR264HR cam...... 487 intake 495 exhaust 264 in duration and 270 exhaust

Weiand Stealth intake or RPM Air Gap
750 speed demon carb

SLP 1 3/4" headers through 2 1/2" dual exhaust

After running several cams through desk top dyno, I really liked this combination.


Here's a little comparision between 3 cams I looked at:


264 peaks are: Horsepower 455 @6000 rpm
Torque 458 @ 4000 & 4500 rpm

270 peaks are: Horsepower 463 @ 6000 rpm
Torque 456 @ 4500 rpm

ZZ4 peaks are: 469 horsepower @ 6500
441 Torque @ 5000

XR264HR XR270HR ZZ4
RPM hp/tq hp/tq hp/tq
2000 157/413 150/395 143/374
3000 249/437 240/420 224/392
4000 349/458 344/451 327/429
5000 428/449 428/449 420/441
6000 455/398 463/405 468/409


Any ideas or suggestions?

 

DON"T BELIEVE desktop dyno!!! Bout a hundred horses more than accual.

 

Yeah, I know it's inaccurate......... 100 ponies extra.........mmmm, I don't think it is that much. I've tested it against some magazine write ups and it is at least more accurate than that.

It doesn't really matter anyway, they are just numbers. What is important to me is when the power happens! It may be inaccurate there too, but it's better than nothing, certainly cheaper than building up and tearing down to replace mismatched parts huh?

 

i don't believe you're going to fit 2.02 and 1.9 valves in a SBC head. like was already said don't believe DD

 

2.02 *1.60 exhaust.

Sorry, type-o!

 

But what about the parts selection? Do they make a good match?

 

Why not a 383?

You have to buy new pistons for a 355, you can reuse the rods, and buy a 3.75" stroker crank. The new crank is the only additional cost to have a 383. For several hundred dollars more, you could have a 383.

I think that a year after you did your 355, you will have wanted to do a 383 in the first place. Anyway, just my opinion.

 

Yeah, I know what you're saying. But the machine work is a little more money too. My main reason for doing the pistons was incase I wanted to do juice on the track..........but that's in the grey area still.

 

Would that cam fit in a 383?

 

I'm building a 383 right now, I'm useing a small base circle cam, eagle sir rods with the small rod bolts. And still had to cut .060 off of the top & sides of the rods. Also running a 600 lift cam. I don't think it cost any more for a 383, unless you don't need a crank. In any case you'll likely need to have it cleaned and polished, that's a 50 spot in my area. 2 hundred more and you got yourself a brand new cast STEEL, [not iron] crank.

 

I'm in the middle of a very similar build up on my 84Z28, except I'm keeping it emissions legal and hence going with the ZZ4 cam to be computer compatible with the feedback Q-jet. I'm doing a 355 also.

I strongly considered a 383 but it adds alot of cost to combine a roller cam 383 with a 5 speed. Probably in the neighborhood of $500-600 more. I decided to stay within my budget and go with the roller cam and maybe the option for aluminum heads, although I haven't bought any yet. Anyway with a 5 speed the extra torque of the 383 is not as significant.

I've got my short block and accumulating all the other parts right now. Like I said I'm still looking at heads. Leaning toward the Edelbrocks because they flow fairly well with smaller ports. And this is going to be purely a street car.

Well good luck
Pete