toolegit86

Building the 1983 camaro z28 l69. My first car back in the day. parents got it new. dad drove it over 300k came with ho305 swapped for 350 with carb, then to a dz302 that exploded the 10 bolt and now to the build you see below

I got a this motor for a racing shop in spokane for 150$ and now i am trying to find out what to do with it
spec:
86 and up block 1piece rear main non roller
center bolt valve covers with the fast burner heads
350 boared 30 over with np345 hypereutectic as far as i know.
gm performance rods
150miles on motor

cheap why??
bad tune and melted one piston
I switched heads with my rock crawler and now have a set with one bad valve.

now i have a ton of older 350 parts i can use. can i put a older set of heads on and run a older intake?

is there a conversion for 1piece to a 2piece rear main?? i have a 400 crank that has been turned to a 350spec

how good are the h345np pistons?? there really cheap? 11.99?

five7kid

iTrader: (14)

Yes.

Yes. It's about $100.

Personally, I'd sell your crank and get a one-piece RMS, internally-balanced 3.75" stroke aftermarket crank. Only con is slightly higher cost in the end (depending upon how much you get for your factory crank), everything else is in the "pro" column. Scat cast steel internal balance 1 piece RMS 3.75" stroke, $243.95, would be tons better than a cut-down factory cast iron crank. Remember, you won't be buying that $100 adapter.

I've been running them since 2005 (the 0.030" version). Street (daily driver, literally) strip (class runner-up for the 2009 season). They are 1.560" compression height, were you planning on using 5.565" rods with the 3.75" stroke crank?

toolegit86

well i am not really worried about the 400 crank its just laying around so i figured i would switch it. and i know if i use the 400 crank i would have to change the pistons to.

i have the motor all torn down sofar my plans are just to ball hone all clynders and rering and rebearing and just replace the one piston and reuse the stock rods.

i am sure they are the powdered metal rods

and is there a part number for that kit or where to get it. its a foged crank. and i have the blancer and 400 fly wheel.

five7kid

iTrader: (14)

If you're talking about the rear main seal adapter, search summitracing.com for "rear main seal adapter".

You said it was a 400 crank turned down to 350 journals.

toolegit86

my bad sorry its a forged crank not cast and my dad said it was a eagle crank that he had turned and poilshed then he gave it to me for free.

five7kid

iTrader: (14)

Ah. Then, it might be worth using the RMS adapter. Can't say I could point you to anyone who has used one, though.

toolegit86

yea i think i will stay with the 350 crank since i will be beating on it on the track. my problem is what heads to run, i have a stock set of the center bolt valve cover heads but i was told there not that good for a high reving motor. i have a old set of 2.02's with manley stanless valves that have been cleaned and ported. or a set of l69 305 heads.

five7kid

iTrader: (14)

What casting #?

Got the casting # of the 2.02's? Manley valves are good, but if the castings aren't the "good" stuff, won't be much help.

The L69 heads would need at least a basic porting job, and 1.94"/1.60" valves would help a lot.

Properly-done Vortec heads would probably outrun any that you mentioned.

toolegit86

ill get the castings here in a bit. i would port the heads as much as i can and get a valve job before i run any set of these heads.

the vortech heads i have came off of my 355cid jeep the fuel injection was out of tune and it burned one valve.so i would need a new valve and a valve job any way. but if i ran these i would need a diffrent intake mani.

so far the car is completly torn down, all seats torn out and paint sanded off with primer.
plans:
get some 1 3/4 tubing and build a 8 point cage
just run 2 apc seats with rci 5points
run some eibach springs with new shocks
go energy suspension poly all around
cowl hood scoop since there is a hole where the last air cleaner came out.
go disk brake rear end (since mine is toast)
corvette zo6 wheels

whats done:
new carpet
all unneeded wires taken care of and a little wire tuck
cleaned and painted engine bay.
y pipe and 3inc straight back to flowmaster (no-cat)
iroc k member and springs
lexan t-tops

motor parts sofar
Pete jackson gear drive
edelbrock performer high rise
holley 650 dp
hedderman headders with y pipe

toolegit86

castin numbers:3978487

i think i am just going to port and get a valve job on the vortech heads and run them. they already have good springs. can you drill the old style intake mani to work on this style head. i really dont feel like buying another intake.

got my piston out and i can tell if it is just cast or hypereutectic cant really read the numbers on this piston all i see is 345np / 645p

five7kid

iTrader: (14)

3973487, perhaps? A "3" can look like an "8". There is no 3978487. But, if they are the 3973487's, those were LT-1 castings, not bad. Big chambers, though.

If the pistons were hypers, the p/n would be H345NP. I believe that cross-hatch pattern on the pin bosses means they are cast, but I wouldn't take that to the bank. I don't recall now what my hypers looked like. The compression height of the cast is 1.540", and hypers is 1.560". The cast are also heavier.

Interesting, on summitracing.com, the 345NP's are $12.95 each and the H345NP's are $11.95 each.

toolegit86

yea i spoke to a rep at summit and he said the cast were known to be better and stronger for a motor that is getting hammered. i dont know. i was thinkin of jsut getting another set of pistons. i plan on building a single turbo set up blown though the carb later so maybe that will be better. i build turbo mani's and set up and tune turbos and supercharged cars so i kind have to do that to mine. mostly to hondas dsm's and the import seen.

it was dark so those heads could be that. they seem to be in good shape ill port and get them tanked and new springs

your going to think i am stupid but the reason i am rebuilding this is because the last motor i had was a actall dz302 it was a tough motor and after a good burn out i exploded my ring and pinion. but the wifes car went t u so i needed a down payment so i sold it. now i have a cobalt ss and no motor in the camaro

five7kid

iTrader: (14)

Cast are better than hypereutectic for power adder, but forged are better than cast.

Sorry about the DZ. There are some things you wish you hadn't let go. I came across some pictures of the CB750 that I had in Germany in the early 80's - I basically took a basket case and made a nice looking bike out of it. But, I was only allowed to ship one vehicle home, and had to go with the practical one (since the first child also showed up while in Germany).

toolegit86

yea the dz302 was a strong motor but it street manners sucked! but once you hit 4k it came alive and could not be touched. and it had to be on race fuel. pump would not cut it.

were you in the service?? i just got activley discharged and can return in 2 months. army rules suck!


I have a old cast np345 piston that came out of a 350 and it looks diffrent then what i have. iam thinkin jsut rering this clynder and get a single rod bearing and run it. like everyone on here i am on a tight budget (expect the first child jan 16) and this motor had less then 150 miles on it.

five7kid

iTrader: (14)

Yes. I was discharged in August.


1982. . .

toolegit86

so i think its a cast piston. ive searched pics on ebay and came up with that you were right. the marks on the side means its cast.

toolegit86

i think i am going to take the valve springs off of the swirl port heads i have and put them on my l69 heads. because of the 58cc chambers and the valve size. i know the heads will die about 5k. but i think the its a better idea then running the 76cc heads with the 2.02's my compression will be like 8:1 and thats pretty low

swirl port casting number: 10110810

toolegit86

now i have to repalce a piston and rod.... the rod bent does any one know what kind of rod that is?