There's no cheap way to make an 18 year old 230HP LT9 engine put out
anywhere near that level of power short of a complete rebuild to a higher
compression ratio, better cam, etc. and ditching the TBI setup. Headers,
cam, intake and larger TBI setup will give you some gains, but involve a lot
of work, a fair bit of time and money and at the end of it all, you've still
got tired low compression engine that is more thirsty and only marginally
faster. I put money, work and time into my '94 Z71 5.7L Suburban TBI rig
when it was three years old to try and get more grunt out of it. Intake,
larger TBI setup, TBI spacer, exhaust, and Hypertech chip....it did get a
bit more mid range torque but nothing dramatic. Not worth the time and
When I say cheap I'm not talkin' happy meal cheap. How about proficiency at
a price point. The truck has 23,000 original miles. So I'm trying to get to
get by with the original rotating assembly. What I need is a top half
rebuild that will get me close to 500hp. Without going over 10/1
compression, without having a top fuel bump stick, and in keeping with the
reliability of the old TBI intake system. I'm willing to pay good money for
parts that will harmonize with my goals. What I don't want is to pay for a
$2,000.00 set of aluminum heads when a cast set with the right grind would
have done the trick.
Getting even close to 500HP the way you suggest simply can't be done.
Intake, headers, a decent cam and keeping the original TBI setup and
chipping it you'd be lucky to see over 325Hp from the original 230HP.
Increase compression how? That takes replacing pistons. Impractical to shave
heads and intake unless you can machine them yourself. The original TBI is
highly restrictive in fuel and air flow. The factory ECM is extremely
conservative for ignition curve, knock sensor input and shift points. The
ECM cannot be reprogrammed like a modern one can, you have to swap it or add
another in conjunction like the Hypertech ones for those years do. Chip
availability is limited now, 18 years after production. Getting close to
500HP from a 230HP engine takes more than minor bolt ons and tweaks.
NEVER going to happen for less than about $5,000.00 and NO way by just
altering the top end only.
The stock lower end will not handle a true 500 HP with the stock crank
and rods. The factory TBI will not flow enough for 500 HP without
computer and hardware modifications. You will have to go to at least
10:1 compression, that means new pistons and rods. You will need a cam
with a VERY non-street/computer friendly grind. Factory heads will have
to go. The ports and quench area won't allow 500 hp.
Your best bet would be to pull the factory engine out, Clean it up and
store it. Then drop a built engine in that can do what you want.
Upon more digging, the 1992 SS454 was a bit different from the '90-91
models.....the cam was better, intake valves bigger, the compression was
higher and it had the L480E transmission coupled with a 4.10 rear end. The
'90-91's had TH400 and 3.73's. HP was up to 255HP and torque to 405ft.lbs.
Very few '92-93 models produced. However, what I said still stands.....no
bolt-ons will get you above 325HP and the TBI and ECM are the major issues.
Of the entire SS454 '90-93 production run of just under 17,000 there were
1380 made in '92 and only 843 in 1993. I would leave it the way it
is.....it's actually quite rare and will be likely be highly collectible at
Steve W is 100% correct. 500HP needs a completely purpose built engine from
the ground up. To put a real 500HP from a 454 in perspective, it's worth
pointing out that the 1970 LS6 was conservatively factory rated at 450HP at
a lower than optimal rpm.....with a more realistic factory output close to
475-480 HP in the OLD gross HP rating system. Simply bolting on tuned
headers, installing a better intake (factory lowrise one needed for
Corvette hood clearance) and rejetting factory Holley 780cfm the put it in
the 550HP range. But that engine was essentially a hand built, factory race
engine with 11.25:1 compression and specialty parts throughout. That same
engine today with those same bolt-ons would be rated around 475HP in the
rating system used from 1972 onward.
Well, start off with what you are willing to spend. It might be
possible to boost your performance by 50-60%, but it would be
helpful to get a ballpark price range.
A crate engine that puts out 450HP is in the $4000.00 range if you
get one of the cheaper units out there.
Look up the price on the following:
New cam plus *all* associated hardware. This will be beyond the RV
or RV2 type cams, I suspect. I'd wager this would be around $500+.
You could use your old pistons and re-ring, but do you want to take
After market TBI or fuel rail system or switch to carburetor.
New intake manifold.
Higher pressure fuel pump if going rail injection.
Chip or interface to tune cam and new fuel/carb system.
New heads or milling cost to work the old heads to add displacement
or to shape up for new/old valves to go with the cam,and port work.
Could come as a complete kit i.e. cam/heads/valves/rockers and such.
Sit down with a local performance shop and tell them what you
want, and they will tell you what it will take. All in all this
step will get you a parts list that will mesh with all of the other
parts so that you may do each modification as a step without the
worry that you are adding a part that will conflict with the
performance of another part.
Cam, heads, carb/injection, intake manifold should all be tuned
for one another.
Last, but not least, exhaust system.
Turbos and blowers are off of the list since they are not cheap.
I recommend getting a crate engine. If you are a DIYer, then
don't plan on doing a weekend job and do a 100% build up of the
existing engine. The caveat being that if the block is weak, the
entire engine will be weak, and that you will end up spending that
same $4000.00, anyway. Save a step.
Usually it's good to start from basic overhauling,
fixing faulty components. Change oils and filters.
Check and fix the brakes! Check rear brake lines
located between frame and gas tank.
For my 1990 ss 454 PU I got:
Edelbrock MPFI and aluminium intake.
Edelbrock #2162 cam and lifters.
Edelbrock #60499 Heads.
Edelbrock Headers and pipes + new cat.
Edelbrock Alum. waterpump
Crane Steel roller rockers
TRW Ls6 pistons
Oversized TBI throttle body.
New GMPP distributor, rocker covers and Edl coil.
Compression aim is about 10:1 instead 7.8:1 original
New oil pump, bearings, air filter, basic overhauling
If everything goes ok with tune up, you only lose 30%
from original 230/245hp (C: )>
This will help to regain original functionality:
Gas prices in Finland 95 oct $7.12/gal
phone edelbrock and see what they got for you , they do a top end kit for your
truck , heads,
intake ,cam ,
if it were me ..id switch to a carb and normal distributor so you can adjust
your timing cure and
set up fuel mixtures ..http://www.summitracing.com/parts/EDL-2095/ ..dont go
looking at there HP
rating thinking your going to get that ..
but im sure something like it will help ...
BTW if you did make 500 HP i have me doubts your tranny would handle it for
even changing rear end gears would make what you have now RPM ( rev ) quicker
gas mileage would go
I have a 90 Chevrolet 454ss with fully rebuilt engine mild race cam everyth
ing internally has been replaced with performance parts, and I’m in
the process of converting it to carburetor, but I’m in need of hel
p don’t know much about these GMs, does anyone know the process on
how to get it rolling, I think I’ve got most parts need for it I?
??ve already installed a edelbrock manifold (7561) Holley 850 brawler s
eries carb, but haven’t Hooked up anything. Parts I’ve got
for the truck
- Msd 6al ign box/ msd mag pick-up distributer(85551)/ coil blaster/ wires
- aeromotive fuel pressure reg (13205)
- sunpro tach
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