block filler in my 400

I was thinking about filling my block up to the frost plugs with block filler on my 400 the engin is going to have 11.5:1 comp or right close to it studded the bottom end
i dont want my bore flexing and 400 are known for that
what is all of your opinions on block filler will it cause it to over heat this is not a daily driver just weekend warior and alittle bit of crueser


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As long as it`s not being used for street duty it`ll be fine on race gas.

e85 110 octane should run like a beast i hope
but i wanted to know more on the block filler i have never used it nore do i know any that has will it make the egine over heat i know the oil will get warmer but thats fine and i would hope to beable to drive it on some sat night piss off the little import driver around here

If you want to drive it at all on the street, I would not want to use block filler, unless you went to some wild overbore.

I know that plenty have done it and its worked out fine, but I would atleast add an oil cooler.

i wouldnt use it on a street motor. if it was just for the track go for it. usually people fill up to the bottom of the water pump holes when using block-crete. not much cooling that way.

i was reading some where up to the frost plugs with the block level

I have filled every 400 stock block engine (7 to date) I've put together with a partial fill. These have all been 550+hp engines in street/strip operation with no overheating issues even when driven to the track 150 mile round trip. Only 400 failure I've had was the first one I built, I didn't do a partial fill and it split a cylinder after a year. I won't build one without filler. The people that talk about overheating because of it are usually people who have only read it in a magazine, along with all the other 400 overheating myths, and don't have actual experience. Just make sure your cooling system is capable of cooling the amount of HP you are intending to make, i.e. treat it like it's a big block.

yes i know all about the 400myth thats kinda how i got the 400 blocks to begin with i know they dont over heat as long as you drill the steam holes but you have ran them with block filler with out any probs on the street once in a wile

Run them on the street all the time. Just make sure your machinist knows about the filler so that he can add about another .001-.0015" piston to bore clearance to account for the increased heat-sink affect as it does tighten up things a little and needs to be allowed for. I fill to about 1/4" below the waterpump holes, and do it before any machining by at least two weeks. Filler will reach about 80% strength in two weeks, and full strength in 30 days

i was thinking i needed to fill it befor it went to the shop i have never done this befor any mput would be very nice

I figure two trips to the shop. First one is for cleaning, boil-out, inspection of wear and magnaflux, then home for the fill and then back to the shop for machining.

all ready done with the first half thanks