HO, Stroker, and Marine performance series engines carry a 1 year unlimited mileage/hour warranty. Coverage is limited to manufacturer and part defects for the Promar Performance engine only. All warranty claims will be determined upon inspection by Promar’s technicians. All non manufacturing/part failures will be assessed and a remanufacturing quote will be provided. If customer denies offer to remanufacture, all parts will be returned to the customer. Labor costs for the removal or replacement of the engine are not covered under this warranty. Non compliance of break in procedures will result in the forfeit of warranty.

Street Strip, Racing Series and Short Blocks of any series carry no warranty due to the nature of use they are intended for.

Promar reserves the right to change vendors or part specifications without prior notification.

All Warranty replacements will be using original engine and parts. New engines will not be provided unless components are deemed useless or do not meet our quality standards.

All HP and TQ ratings are achieved on a Superflow Dyno in a controlled environment for and tuned for optimal performance output.

Please go to the link below to view our stock replacement warranty.


Engine cannot have been installed and may not be returned after 15 days from invoice date. Customer is responsible for all shipping charges and a 20% restocking fee before any refund. Refunds will be credited after an examination of returned product is complete. Any damage cost will be taken from refund amount. On all performance engines authorization must be received prior to return.

Here at Promar we strive to provide the Highest Quality Engines to set the standard of the industry

Before Start up double check all connections, such as fuel system connections, electrical connections, cooling connections, and vacuum connections.

We Recommend the use of 92 Octane fuel in all of our performance engines except racing engines.

Use one of the following engine oils for break in: Joe Gibbs Racing 30wt, Brad Penn Racing 30wt, Valvoline Racing 30wt, Rotella T, Or use 1/2 qt of GM part number 88862586 E O S with regular 30wt engine oil.

If possible, fill the engine with coolant at the intake manifold with the thermostat housing removed. This will aid in removing any air pockets in the engine.

Always Prime engine prior to start up. There are many tools on the market for priming many different types of engines. Most are reasonably priced or you can make your own tool. What ever you choose to do, just keep in mind that priming the engine is a MUST.

Set initial ignition timing at 10 deg and set max advance at no more than 36 deg.

Once you fire the engine up, observe oil pressure, coolant temperature, and listen for any odd noise. Also check for fuel, coolant, and vacuum leaks.

The proper break in for a non Dyno tested Promar engine is as follows: Run the engine initially for no less than 20 minute’s. Vary the RPM between 1800 and 2300. Do not idle the engine during initial break in.

In the first 500 miles avoid excessive constant speed driving such as highway driving. Fluctuating speed and RPM will give you the best break in results.

Change the oil at 500 miles using same grade of oil as originally recommended.

Normal highway driving is allowed after first oil change but you must change oil again at 1000 miles and then every 3000 miles thereafter using a high grade 10w 30.

For dyno tested engines skip cam break in as this was already performed on the engine Dyno.

Use one of the following engine oils for break in:

Joe Gibbs Racing 30wt
Brad Penn Racing 30wt
Valvoline Racing 30wt
Rotella T 15w-40
Or use 1/2 qt of GM part number 88862586 E O S with regular engine oil.

Drive engine for 500 miles change oil and filter
Repeat use of performance oil or additive
Change oil and filter at 1000 miles
Use high grade non synthetic 10w 30 every 3000 miles after

Failure to follow this procedure will result in the forfeit of warranty
Retain all oil and filter receipts to insure proper warranty coverage