Beefing up an 84 Crossfire Engine?
Thread Starter
Intermediate
Joined: Jun 2011
Posts: 45
Likes: 0
From: CANISTEO New York
Beefing up an 84 Crossfire Engine?
Evening all,
My 84 hasn't been driven in awhile, 2 years in fact, but am about to put her back on the road and want to "beef her up" a bit before I do.
The old Crossfire has 75,000 miles on it and while it runs very well I am becoming disenchanted with the power it produces, 225 BHP. What I'd like to do is give it a bit more get up and go and perhaps up the HP to the low/mid 300 HP.
I have considered dropping in a new custom built motor (450 HP) for around $5,000 but if there is a cheaper way of bringing new life to this motor I would be interested (very interested) in hearing any advice.
Basically, what can I do to increase the HP and general performance without having to be Bill Gates to do it?
My 84 hasn't been driven in awhile, 2 years in fact, but am about to put her back on the road and want to "beef her up" a bit before I do.
The old Crossfire has 75,000 miles on it and while it runs very well I am becoming disenchanted with the power it produces, 225 BHP. What I'd like to do is give it a bit more get up and go and perhaps up the HP to the low/mid 300 HP.
I have considered dropping in a new custom built motor (450 HP) for around $5,000 but if there is a cheaper way of bringing new life to this motor I would be interested (very interested) in hearing any advice.
Basically, what can I do to increase the HP and general performance without having to be Bill Gates to do it?
Instructor
Joined: Nov 2013
Posts: 154
Likes: 1
Evening all,
My 84 hasn't been driven in awhile, 2 years in fact, but am about to put her back on the road and want to "beef her up" a bit before I do.
The old Crossfire has 75,000 miles on it and while it runs very well I am becoming disenchanted with the power it produces, 225 BHP. What I'd like to do is give it a bit more get up and go and perhaps up the HP to the low/mid 300 HP.
I have considered dropping in a new custom built motor (450 HP) for around $5,000 but if there is a cheaper way of bringing new life to this motor I would be interested (very interested) in hearing any advice.
Basically, what can I do to increase the HP and general performance without having to be Bill Gates to do it?
My 84 hasn't been driven in awhile, 2 years in fact, but am about to put her back on the road and want to "beef her up" a bit before I do.
The old Crossfire has 75,000 miles on it and while it runs very well I am becoming disenchanted with the power it produces, 225 BHP. What I'd like to do is give it a bit more get up and go and perhaps up the HP to the low/mid 300 HP.
I have considered dropping in a new custom built motor (450 HP) for around $5,000 but if there is a cheaper way of bringing new life to this motor I would be interested (very interested) in hearing any advice.
Basically, what can I do to increase the HP and general performance without having to be Bill Gates to do it?
If I owned an 84 which I'd like to one day especially for how affordable they have become, here's what I would do. Port match the intake( I hear that alone is good for for 20hp),
have the throttle body's rebuilt and balanced, long tube headers, springs and 1.6rr's, update that nylon timing gear set with a steel replacement, fresh tune up with new coil/plugs/wires. Think this would cost alot less than replacing the engine and really wake it up. Especially if you do the work yourself. Good luck
Thread Starter
Intermediate
Joined: Jun 2011
Posts: 45
Likes: 0
From: CANISTEO New York
If I owned an 84 which I'd like to one day especially for how affordable they have become, here's what I would do. Port match the intake( I hear that alone is good for for 20hp),
have the throttle body's rebuilt and balanced, long tube headers, springs and 1.6rr's, update that nylon timing gear set with a steel replacement, fresh tune up with new coil/plugs/wires. Think this would cost alot less than replacing the engine and really wake it up. Especially if you do the work yourself. Good luck
have the throttle body's rebuilt and balanced, long tube headers, springs and 1.6rr's, update that nylon timing gear set with a steel replacement, fresh tune up with new coil/plugs/wires. Think this would cost alot less than replacing the engine and really wake it up. Especially if you do the work yourself. Good luck
Appreciate your input, cheers.
Le Mans Master
Joined: May 2004
Posts: 5,386
Likes: 534
Intermediate
Joined: Mar 2015
Posts: 31
Likes: 0
From: Frazier Park California
Interesting. I just bought an '84 that has a 383 bottom end and Edelbrock Performer heads. Supposedly, the intake has been port-matched, but I can't verify. Unfortunately, it still has the stock Crossfire system and totally lays down at 3500 RPM.
Kind of thinking of swapping to a carb while save for an LS swap.
Kind of thinking of swapping to a carb while save for an LS swap.
Pro
Joined: Jan 2003
Posts: 706
Likes: 47
From: Denver Colorado
Interesting. I just bought an '84 that has a 383 bottom end and Edelbrock Performer heads. Supposedly, the intake has been port-matched, but I can't verify. Unfortunately, it still has the stock Crossfire system and totally lays down at 3500 RPM.
Kind of thinking of swapping to a carb while save for an LS swap.
Kind of thinking of swapping to a carb while save for an LS swap.
Intermediate
Joined: Mar 2015
Posts: 31
Likes: 0
From: Frazier Park California
If you still have the stock TBIs on a 383, even with the stock intake ported, you are restricted by the size of the bores on the TBIs. There used to be a shop in Arizona that could bore the TBIs and increase the airflow. You would have to tune of course. Sorry, I don't recall the name of the shop but... they were also involved with the "Renegade" intake for Cross-Fires.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Jun 1999
Posts: 2,931
Likes: 127
From: Ashland Alabama
No.
If you can tbi a 454 you can boost that current system to feed a 383.
If its falling on its face horrible at 3500 you have something wrong besides throttle body size.
Two Crossfire Throttle bodies bored to 2.375" will flow over 1,000 CFM. The biggest thing isn't air needs its injector size for that kind of mod.
Summit racing has aftermarket intakes for them now too. So I wouldn't ditch the crossfire if it was me.
But back to the falling on its face part. I bet something is not right somewhere causing your problems. So more diagnosing less replacing
If you can tbi a 454 you can boost that current system to feed a 383.
If its falling on its face horrible at 3500 you have something wrong besides throttle body size.
Two Crossfire Throttle bodies bored to 2.375" will flow over 1,000 CFM. The biggest thing isn't air needs its injector size for that kind of mod.
Summit racing has aftermarket intakes for them now too. So I wouldn't ditch the crossfire if it was me.
But back to the falling on its face part. I bet something is not right somewhere causing your problems. So more diagnosing less replacing
Pro
Joined: Jan 2003
Posts: 706
Likes: 47
From: Denver Colorado
I would not carb it either. The TBI system can be made to run good. It just takes persistence and finding the right combination. Going to a carb requires a lot of other changes that greatly complicate the project. To me, your laydown at 3500 RPM sounds like another fuel pressure problem, should be 13 psi or so under acceleration, but trying to diagnose at a distance is always risky. Have you checked fuel pressure?
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
No.
If you can tbi a 454 you can boost that current system to feed a 383.
If its falling on its face horrible at 3500 you have something wrong besides throttle body size.
Two Crossfire Throttle bodies bored to 2.375" will flow over 1,000 CFM. The biggest thing isn't air needs its injector size for that kind of mod.
Summit racing has aftermarket intakes for them now too. So I wouldn't ditch the crossfire if it was me.
But back to the falling on its face part. I bet something is not right somewhere causing your problems. So more diagnosing less replacing
If you can tbi a 454 you can boost that current system to feed a 383.
If its falling on its face horrible at 3500 you have something wrong besides throttle body size.
Two Crossfire Throttle bodies bored to 2.375" will flow over 1,000 CFM. The biggest thing isn't air needs its injector size for that kind of mod.
Summit racing has aftermarket intakes for them now too. So I wouldn't ditch the crossfire if it was me.
But back to the falling on its face part. I bet something is not right somewhere causing your problems. So more diagnosing less replacing
100% I ran a ported CFI on a small block 400 and it would pull well to 5k. In fact, 5k was my shift point at the drag track.