Engine & Exhaust / Q&A / Tech

Mailbag: Calculating Compression Ratio and Building LT1 Power

Got questions?

We’ve got the answers—Mondays when the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re talking compression ratio and LT1 power.

From: John Oltman, Jr. • Metamora, IL
Q: I’m rebuilding a 327 to drop into my 1948 Jeep CJ2A. I’ve bored the engine .030 inches over and equipped it with 180cc Airflow Research heads, flat top pistons, a Lunati Voodoo cam and lifters, a Weiand Stealth intake, a Holley 600 cfm carb, and an MSD Ready-to-Run distributor. Can you tell me what the compression ratio would be?

A: There are some handy tools out there to help you with tricky calculations such as compression ratio. Summit Racing, for example, offers a variety of helpful automotive calculators and tools, including:

To find your engine’s compression, click the Compression Calculator link above, fill in your engine specs, and click calculate—it’s that easy! Be sure to have the relevent info on hand (bore, stroke, cylinder head volume, etc.) for even quicker calculations. If you run into any snags, Summit Racing’s tech staff can help you get the final answer you need.

From: John Patrick • Taylor, MI
Q: I have a 1997 Camaro SS with an LT1 engine. What is the easiest way to gain horsepower without totally tearing the engine apart? Also, will 17 x 11 wheels fit into my rear wheel wells or would I have to modify them to fit?

A: For a solid foundation of power, we recommend a cold air intake and a performance programmer. Both are easy to install and create big performance gains. As for the cold air intake, your best bet would be the K&N Generation II FIPK (KNN-57-3010-1). It has an advanced free-flowing design that dramatically reduces air intake restriction for up to a 10 percent increase in horsepower. Then for the performance programmer, you can install the Hypertech Power Programmer III (HYP-30027). Just plug it into your OBD port for noticeable increases in horsepower and torque throughout your entire powerband. Combined, the intake and programmer will transform your Camaro into a serious street machine!

Regarding the wheels, it would take a lot of modifications to make those 17 x 11 rims work. Your Camaro can accommodate up to 9 ½-inch wide wheels with 7-inch backspacing.

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  1. Yes, 17×11″ wheels will work with up to a 305 wide tire. This has been a common mod. I currently have 18×10.5 wheels on my 95 Z28 with a 295 wide tire and it clears fine. On that note the camaro SS came stock with 9.5″ wide tires. Also don’t waste your money on a hypertech, the best bang for the buck I did to mine was cold air, headers and 1.6 roller rockers with a good computer tune using “tunercats”. I live summit but this was pretty crappy advice regarding the LT1 Fbody.

  2. The issue with the wider wheels comes in of the carbs lowered, then the Panhard bar shifts the rear to the drivers side slightly. In this case and adjustable Panhard bar will center the rear and the wheels will still fit. Mine has BMR 1″ lower springs and the Panhard bar and don’t rub.

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