My target power level at the wheels is 550-600hp max with daily driving street manners. Until today I was pretty much settled on going FI but after more thought and research I'm not so sure.

I really want to be able to drive my car hard and may even attend a few DE's. It appears that very few road race guys are FI due to reliability concerns and only recommend NA motors. I have owned a few FI-supercharged cars and I know firsthand what heat can do even if the car is well tuned so I understand the concern.

For you guys with 427 conversions can you tell me if you are having engine cooling problems under day-to-day/hard driving conditions. Specifically are you having problems with high water and oil temps with all accessories and HVAC on? I've read and heard that 7.0L engines in C5's are very tempermental. If I remember correctly the reason the C6Z has a much wider front opening than the non-Z cars was to permit increased airflow for the cooling the 427 motor requires - frontal area the C5 does not have.

All feedback appreciated.

-RR

 

Get on the track and driver first before any HP mods.

We tell ppl the order of modifications are Contact patches first.

Brake pads and Fluids
Seat and harnesses
tires

Then cooling

Trans and oil cooler, accu-sump too

Then after you have gotten your lap times down as low as you can, then a little more HP.

99.99% of vette drivers can NOT drive the stock vehical to its limits.

BIG HP numbers look cool and are great for bench racing, but it DRIVER SKILL that will get you lower lap times, not HP, at first.

 

Thanks however that doesn't really answer my question.

I don't plan to ever make my car a track only or track purposed car. I just want it to be reliable should I upgrade the powerplant to a 427 for day-to-day/hard driving on every day-roads, highways and interstates; conditions where it will spend 99% of its time.

Any other feedback from owners who have done the conversion?

-RR

 

I don't think you are going to get too many replies to your query because I don't think there are that many C5 owners that have done the 427 conversion and track their cars.

Might be better off modifying question to include people who have gone with 402 and up, or instead of focusing on engine size go by HP, say 500 to 550 rwhp. Much bigger population. Don't know if you posted this in auto-cross/road racing section but might be worth a shot.

FWIW, I have been thinking along the similiar lines as yourself and have decided that NA is the way to go. Too many heat problems with FI and all the extra HP does not seem to result in significantly improved times. Those that chose the turbo route seem to have the most problems with the heat, but also modulating the power because the turbo power is non-linear. There was a post about this some months ago in the road racing section. If you do a search you might find it if you put FI in your search criteria.

Also, rather than focus on HP numbers I would suggest looking at torque numbers as torque is what accelerates the car. The bigger block motors offer significantly better torque than the smaller block motors. I guess lends credence to the old adage that there is no substitute for displacement. You might want to look at the engine specs for the C5R and C6R. What I found interesting is that with the C6R, GM focused on torque more so than HP and look at how well the C6R has done.

Here is a link for you.

http://www.corvetteracing.com/cars/c...ne_specs.shtml

 

For the most part a 427 does or should have a larger radiator for any hard driving.

for track events, look to put in a dry sump oiling system. Yes this does add considerably to the initial expense, but will make the engine much stronger and last.

with that much HP in mind I am sure you are also looking at stregthing the trans / diff and hardened out put shafts too.

 

I converted to a 427 last May. The engine was blueprinted and built by MTI Racing of Atlanta. My car was a daily driver until July of this year when I purchased a beater to drive to work each day for gas reasons. I drive about 32 miles one way each day in stop and go Atlanta traffic. I have over 18,000 miles on the motor and never a problem. I did install a larger radiator (Ron Davis) and oil cooler but otherwise no additions. I have a mild cam and see over 600 bhp and 600 btq. I would have opted for a much more radical cam but since it was a daily driver I opted to stay conservative. Your builder is the most important decision you will have to make. This is very important as this will dictate how much or little you will enjoy your car. I have been so pleased I am now looking at upgrading to a 454ci engine. Frankly, there is no enjoyment like the huge low end torque you get from cubic inches. There are several MTI Racing customers that have upgraded to 427 engines and they all road race them and two customers that drag race and both run in the 9's.
Good luck on your decision.

 

I have the Lingenfelter 427 (for over 3 years).

Do NOT track the Vert.

Do have the electric water pump, and over sized radiator.

Driveablity - great, but it is more than necessary (IMO). Example - the S/O has the Lingenfelter H/C, Kooks, under- pulley, 4:10's - much more refined, and more than enough power (440 RWHP).

If I were to do it again - hers is the setup I would opt for.

As to numbers: 519 RWHP

 

Thank you, I appreciate this very much it's exactly the source of feedback I need to make a good decision. I agree with you that the builder is key and had already decided to return to LPE for the upgrade.

Thank you too. FWIW, I currently have the same package as your S/O; installed by the same fine group of guys. However now I'm ready to step it up because I want more power especially low end torque. I am curious though about what you mean when you describe her package as "more refined" than your 427 package.

-RR

 

RR

The 427 is massive HP - really overkill for the street.

Very hard on tires (a set of Mich PS2's may get you 12k miles) - even if you don't race.

The rear is prone to 'kicking' out under ~1/2 throttle - one reason the tires don't last long!

As for low end torgue - if it is SOTP you want, get a set of 4:10's. The S/O Vert pulls me from a hole shot

 

Okay, I see your POV, but that's kind of what I want. I have 3.90's now and although a definite improvement in torque multiplication, I miss the loss of max speed in 5th. I'm going to run in next year's One Mile Shootout here in NE and I don't want to be handicapped.

Thanks for the feedback!

-RR

 

The power just needs to be respected. I have friend that has almost 1000bhp and he drives on the street. I also have a 3.90 rear and it is useless to really get on it in 1st or 2nd. You just will learn to drive a little differently with that power. If you have selected LPE then you have made a selection you can trust to give you a dependable and driveable car.

 

3.90 gear with the 427?!?!?!?! You da man! Thanks for all the info.

-RR

 

What if you just want to go fast, on the street, in a straight line?

 

^^You will at least need a larger radiator to handle the extra heat.

 

RR -

Do a search and you will find everything you need on this subject! First decision is use a C5-R block or sleeve another or use one of the modern 427 blocks each has pros and cons!

JR