SteveG75

OK. Old engine is out but I still have to figure out what I want to put in there.
Went to see a local engine builder today about building up the old L-48 to about 400 HP. His opinion was it was better to store the old one and build a new 4-bolt main.

Anyway, I am thinking of the following combo:

ZZ4 short block (GM)
AFR 190cc heads , 68 cc for 9.5:1
GM HOT cam (hyd roller 218/228 @.050, 112 LSA, .525" lift with 1.6 roller rockers) (very easy to fit into the ZZ4 block)
Performer 2101 (for now so hood fits)
Q-jet (to be rejetted of course)
HEI
Dynomax 1 5/8" headers with duals

Dyno 2000 shows 429 ftlbs at 2500 and a peak of 454 ftlbs at 4000. Stays above 400 ft lbs till 5500 rpm. Horsepower peaks at 416 @ 5500. Yeah, I know Dyno2000 isn't as good as Engine Analyzer but it is fun to play with.
:smash: :smash:


[Modified by SteveG75, 6:49 PM 1/12/2002]

Armstrong

I'm not an Engine GURU but that sure sounds SWEET!!! to me

topless68

Steve,

I am wondering why he suggested a 4 bolt main? 4 bolt mains are way overrated and have personally rec'd good service from two bolts. (450hp and over 6500 rpm)

What compression ratio are you shooting for?

Your head selection should be fine if the valve size is adequate...2.02 intake and 1.6 exhaust (if they have 2.08 intake available, I would opt for that, if inserts will handle.) Also, I assume we are dealing with 350 cid? and possibly 355 if your block is bored?

Your cam is my next question. The LCA at 112 is a little wide. I will have to know your cid before recommending an LCA, but usually a tighter LCA at around 108 is a better fit. The duration is a little tight also for a small block trying to make 400+ hp. You'd like to see something in the 240-250 duration range @ .050 to open the valve a little quicker....don't get me wrong, there is nothing wrong with the cam selection, but IMHO if you want to see 400hp in 350ci you need to expand the duration a little bit. Lift is fine. Roller rockers, with a 1.6 on the intake will really help also.

If you don't mind...I still would like to know cid and compression you are shooting for...and BTW, what size CC do the heads have?




[Modified by topless68, 5:12 PM 1/12/2002]

SteveG75

Topless,

Compression is about 9.6:1. Heads are 2.02/1.60 valve sizes.

I know the cam seems small but it is a roller setup. This is the same cam that GM put in the ZZ430 (430 hp with the Fastburn heads) and CHP did a buildup with Vortec heads (not even ported) and got 420 HP on the dyno. 1.6 rollers on each side get the .525 lift.

Anyway, sat down and did the #'s. About $4800 with all top of the line components (Fluidampner, Moroso pan, etc) :nopity

Maybe time to revise my expectations.

74-Roadster

:crazy: Don't hold back now!!!! You'll only regret penching pennies! :D :D I think you ought to look into a custom 383 from Street & Performance (with TPI of course)! If I decide not to build my own, I bet that's where I end up! I'm trying to save now so I can afford it in 5-6 years when everything else has been rebuilt. I figure the engine will be the last step, who knows what will be available in a custom LS-6 by then. :cool: :cool:

As fast as your car looks, make sure the engine can back it up. You should only consider losing to a Z06 or Viper!

Good Luck and keep us posted. :D

79er

A small block 406 will fit great and with it, it's easy to reach 400hp.


[Modified by 79er, 10:35 PM 1/12/2002]

topless68

Not necessarily. Remember, these numbers are dynoed, meaning they put an engine on and tweaked it, probably with some of the best carb people in the industry. I've seen engines built, and would tweak them to what I thought would be optimal numbers (just from past experiences, crunching numbers, bench racing) and the motor turns out to be dog at first. After rejetting, and timing, changing plugs, pulled another 40-45 hp out of it. They also have optimal fuel/air temp and ratios which changes dynamics. Not trying to be pessimistic at all, but remember that when you first fire it, alot of tweaking and adjusting is needed to squeeze those extra ponies out.

Copying a proven, previously dynoed motor is hard to beat. I see in your sig that your car is daily driven. If it is...10:1 CR and a cam I previously mentioned is very streetable but might not be practical for daily driver.

One more thought. Depending upon your machine/assembly capabilities, your current 350, built at home by yourself could probably net you around $2000 in savings if you build yourself. That is if scour swap meets for a few goodies here and there...mainly your heads. Just my .02.

Good luck, and I hope I haven't steered you wrong.