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The Boostline 5.7 Boasts 571-Horsepower On A Budget

Nick Adams July 20, 2026 5 min read 0

There is no way around it; horsepower costs money. In recent years, that cost has been rapidly rising to eye-watering levels. It’s no wonder younger generations are focusing on vinyl wraps and cheap wheels from Alibaba rather than improving performance. But the team at Boostline Performance knows that a majority of us are looking for reliable horsepower without pockets as deep as the Grand Canyon, and their Street Series LS short blocks and long blocks fit the bill. Their latest Boostline 5.7 package utilizes BTR’s latest canted-valve cylinder heads to make some very impressive numbers on their in-house engine dyno.

What is a 5.7 LS?

The 5.7-liter LS famously came in LS1 form under the hoods of F-bodys, GTOs, and C5 Corvettes, and as the more potent LS6 in the C5 Z05 and CTS-V. But the aluminum blocks can’t accept much of an overbore to rebuild, and are still costly on the second-hand market. The trick is to take the truck 4.8 and 5.3 blocks and bore them out to the same 3.898-inch bore as the LS1/LS6 to make a budget iron version. Thankfully for us hot rodders, GM left plenty of meat in the cylinders to handle the 0.118-inch overbore.

The Boostline 5.7 proves you don't need a huge budget to make serious LS power. 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BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - 003 - Car Junkie Mag - The Boostline 5.7 Boasts 571-Horsepower On A Budget - Car Junkie Mag - 5.7 LS engine - The Boostline 5.7 proves you don't need a huge budget to make serious LS power. BTR's canted-valve heads pushed this mild 346ci combo to an impressive 571 horsepower. - Boostline 5.7 - Car Junkie Mag

Boostline Performance in Wichita Falls, Texas knows a thing or two about rebuilding engines, especially the GM LS V8, and now offers options from budget stock-level rebuilds to get your truck back on the road, to 454-cubic-inch strokers to power whatever project you’re dreaming of. Their Boostline 5.7 Street Series comes in short block and long block form, with 243/799 casting cylinder heads on the long block version. But when Brian Tooley Racing debuted their canted-valve cylinder heads for the LS, and word got around about how much performance they deliver over most aftermarket castings, Boostline Performance had to see what they could do.

The Boostline 5.7 LS

The Boostline 5.7 was pushed into the dyno room and strapped down to get a baseline run. We’ve all seen the power gains when these heads are swapped on, from 2,000 horsepower to 2,150 horsepower in Brad Thiessen’s turbo Nova when going from TrickFlow to BTR’s CVH heads, to BTR’s in-house dyno testing picking up to 100 horsepower naturally aspirated on a stock LS3 short block, so Boostline Performance had a unique idea. Instead of swapping heads on a big-inch, big-cam LS, which would undoubtedly gain a massive jump in power and torque, they wanted to truly test their capabilities on something mild like a 346-cubic-inch LS with a BTR Truck Norris cam.

A Boostline 5.7 Street Series engine with the BTR Truck Norris cam is a great all-rounder for someone who wants a daily driver-quality truck engine that sounds mean at idle and makes great power and torque. It could work for a muscle car, classic truck, or if you just want your GMT800 to get back to work. But with only 212 degrees of intake duration and 0.553 inches of valve lift, is it even worth swapping from the best cathedral port casting GM offered to a fully CNC ported cylinder head?

Basline Dyno Numbers

The baseline numbers were 517 horsepower and 479 lb-ft of torque. For a pump gas-friendly LS with stock block, heads, crank, rods, and pistons that you could daily drive, these are impressive numbers. But it’s time to see if the BTR CVH heads can give us the gains on this Boostline 5.7 as they have for everyone else. Off came the stock 243/799 casting heads and on went the BTR CVH LS3 heads. These heads accept LS3-based rectangular-port intake manifolds and fit LS engines with a bore as small as 3.820-inches.

The BTR CVH LS3 heads have the same 64cc combustion chamber as the stock heads, so the compression remains the same at 10.5:1. The BTR heads use the same exhaust port layout and valve cover mounting as stock, so no special tricks to get them swapped onto the Boostline 5.7. After the head swap, the engine was brought back up to the same operating temp as the stock-cylinder-head run and ran again.

BTR CVH Dyno Results

The results? A gain of 54 horsepower and 16lb-ft of torque for a grand total of 571 horsepower and 495 lb-ft of torque! And like the dyno testing done by other BTR customers and independent tuning shops, those gains came with no loss in low-end power. Going from a stock casting to an aftermarket canted valve casting on such a mild combo and picking up these kinds of gains is beyond impressive. If these gains can be had with a low-lift cam, imagine if they went further with one of BTR’s larger grinds.

At the time of writing this, Boostline Performance is giving away this Boostline 5.7 Street Series engine with BTR’s heads. Go to their website to see the rules, and maybe you can get 571 horses under the hood of your truck or project before time runs out. If you missed the giveaway, the good news is Boostline will build you whatever LS you like. The sky (and your bank account) is the limit!