Will this help to stop a block leak where the water pump connects to the cooling system?

No. This will only help with small leaks. As temp fix.

Can it be used on 1968 327cid for leaking freeze plug?

Yes, Our formula permanently repairs larger leaks in radiators, intake manifolds and gaskets, heater cores, blocks, heads and freeze plugs. It contains an antifreeze-compatible sodium silicate liquid glass formula, so no draining of the cooling system is required. Not to mention, it will not harm the cooling system when used properly. The intake gasket seal you’ve been looking for is far more effective, easy to use, and less expensive than you’ve ever imagined. This is why Bar’s Leaks exists: to offer usable, low-cost intake gasket seal and other products to auto owners who have no special experience or expertise. We’ve been doing this for over 70 years, so we know a thing or two about chemical repairs. One bottle treats cooling systems from 12 quarts (3 gallons) to 24 quarts (6 gallons). Use 1/2 bottle for cooling systems from 8 quarts (2 gallon) to 11.9 quarts (2.99 gallons). For larger systems use one bottle for every 6 gallons of cooling system capacity. Small engines or other small systems use approximately 3 fluid ounces per gallon of fluid capacity. If you have any other technical questions, feel free to contact our Technical Service Professionals at 800-345-6572 or if you would prefer you can use the contact us page on our website.

heater core leak fixed?

The label on the lower right does show Heater Core. So this could work since coolant is being pumped through the heater core to heat the cabin of a vehicle.

Can this help with a 5.3l gm engine with the bad cylinder head castings? i'm saving for a replacement engine, just need this one to last a while

Thanks for your question, and for considering Bar's Leaks to help with your vehicle's needs. The product you are asking about - Bar's Leaks Block Seal Intake & Radiator Stop Leak is a great product for repairing larger leaks in radiators, intake manifolds & gaskets, heater cores, blocks, heads and freeze plugs. However, if your vehicle is showing signs of head gasket failure due to the bad castings you refer to, we would suggest one of our head gasket products, such as Head Gasket Fix (part number 1111), which is very successful in sealing leaks as long as your vehicle can run 20 minutes or longer without overheating or needing to add coolant. If your vehicle is unable to run for 20 minutes without overheating, but can run for at least 15 minutes, we recommend our strongest head gasket stop leak - Head Seal Blown Head Gasket Repair (part number HG-1). For best results, these products should be installed into a clean cooling system, following the installation instructions and proper dosage. If you are unsure how clean your cooling system is, or you haven't had it chemically flushed in the last three to four years, we recommend doing so before installing any stop leak products. If you have any other questions, or we can be of further assistance, please feel free to call our Tech Support team at 1-800-345-6572. We are here to assist you Monday through Friday, from 8 am to 5 pm, Eastern time.

Manufacturer	Bar's Leaks
Brand	Bar's Products
Product Dimensions	19.05 x 6.6 x 6.6 cm; 589.67 g
Item model number	1109
Is Discontinued By Manufacturer	No
Item Dimensions L x W x H	19.1 x 6.6 x 6.6 cm
Item Weight	590 g

Engine Oil Stop Leak Pack of 1 1109

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