Flag Motorsports

Flag Motorsports Flag Motorsports is a high performance engine building shop specializing in LS and LT engines. We are located in San Marcos, CA and ship nationwide.

Check out our website to get in touch regarding an engine build!

May have forgotten to post Kevin's LT4 build that we wrapped up a bit ago, so here's some beauty shots! Kevin brought us...
07/31/2026

May have forgotten to post Kevin's LT4 build that we wrapped up a bit ago, so here's some beauty shots! Kevin brought us his bare block from Arizona and trusted us to do all of the machine work and assembly. He had been proactive and bought many of the parts he wanted used in this build, which was awesome! We ran into a small issue with the pistons he'd originally bought - they were set up for NA and his was a boosted build so his compression ratio would have been too high. Luckily we had a set of boost pistons in stock and were able to pivot and get him the right parts for his engine. Making sure every part works together in an engine recipe to meet the goals of the project is one of the trickiest parts of any build! Here's the combo details:
GM LT block honed on our Rottler H85A, surfaced on our block machining center, and align honed with ARP main studs.
GM LT1 crankshaft balanced on our Fentech DCB2000.
Callies Performance Products connecting rods and CPCarrillo Pistons & Rods pistons with ACL main and rod bearings.
Katech Engineering LT wet sump billet gear oil pump and timing chain.
Texas Speed & Performance front cover, valley cover, and timing chain guide.
Ported LT1 heads with ARP head bolts, CHE Precision Inc. rocker trunnion, Brian Tooley Racing spring kit and camshaft.
ATI PERFORMANCE PRODUCTS, INC harmonic balancer provided by Gabriel Griffin!

Looking for an LT engine builder who can do machine work and assembly in house? We've got your back. Kevin's badass LT1 ...
07/20/2026

Looking for an LT engine builder who can do machine work and assembly in house? We've got your back. Kevin's badass LT1 rebuild for boost just wrapped up, full build gallery coming soon!

Don't forget to check your oil squirters on these LTs, make sure you have piston clearance at the bottom of the stroke, ...
07/18/2026

Don't forget to check your oil squirters on these LTs, make sure you have piston clearance at the bottom of the stroke, and rod clearance at the lowest point.

Come on over to YouTube for a full technical break down and application commentary with 10 different LT pistons. Piston ...
07/17/2026

Come on over to YouTube for a full technical break down and application commentary with 10 different LT pistons. Piston design, skirts, wrist pins, ring packs, weight, etc are all covered!

After a controversial and poorly worded Instagram story on my part ...

Doug's fully forged LS3 stroker shortblock all ready to go for whichever project he puts it in! Doug has a fleet of like...
07/16/2026

Doug's fully forged LS3 stroker shortblock all ready to go for whichever project he puts it in! Doug has a fleet of like 30 LS cars and most of them are boosted. Everyone should be like Doug. 🤘

Address

635 N Twin Oaks Valley Road Unit 3
San Marcos, CA
92069

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