Engine gurus - opinion please
Thread Starter
Race Director
Joined: Jun 2000
Posts: 10,045
Likes: 675
From: FL
Engine gurus - opinion please
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]
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]
Melting Slicks
Joined: Aug 2001
Posts: 2,833
Likes: 15
From: Southeast La
Re: Engine gurus - opinion please (SteveG75)
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]
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]
Thread Starter
Race Director
Joined: Jun 2000
Posts: 10,045
Likes: 675
From: FL
Re: Engine gurus - opinion please (topless68)
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.
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.
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
Re: Engine gurus - opinion please (SteveG75)
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.
Maybe time to revise my expectations.
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
Melting Slicks
Joined: Aug 2001
Posts: 2,833
Likes: 15
From: Southeast La
Re: Engine gurus - opinion please (SteveG75)
Maybe time to revise my expectations.
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.
