I want to have a short block done up by a machine shop. I have a 109 block-standard bore, rusty cylinder walls and deck. I have a hotair block that is in better condition. It will be for a street car that will not see any times faster than 11 seconds flat. My question is: is there really that much more advantage in using the 109 block over the hotair block? It seems like the everybody considers the 109 block to be alot more valuable over the hotair block. I have solved the oil return issue, with a fitting on the passenger side of the oil pan. I currently run a hotair block/ converted to an 87 set-up, and it runs very well. The few differences in blocks that I am aware of is the oil return hole, lower deck height for the 109 block, and water drain passage(not a big deal). Are there any significant strength differences for a engine developing less than 500 hp? I will be using the two center billet main caps, high strength rod bolts, forged pistons, and head studs.
109 vs hotair block
- Thread starter garrett
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Lee Thompson
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Imo
@ the HP level you are shooting for, the HA block will get the job done, assuming it is CLOSE to std. bore.
@ the HP level you are shooting for, the HA block will get the job done, assuming it is CLOSE to std. bore.
Just a Six??
OK! Who Farted??
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Guys have run them into the 9's. 10"s with NA Cranks! There was a big debate over the nickel content issue or something like that & they are virtually the same. FLAME SUIT ON!! 
I have 2 turbo blocks & am now building a NA with good parts like the others for my own knowledge. The KEY is NO (or very little) Detonation, but that applies to both of them! Mine are in the 600HP range altho, at 30 over, I would probably take the the turbo block. Just because its been engrained into my mind over the years I guess????? I would bet that at 500 HP & again No Detonation you will be fine. I race mine quite a bit but for a friendly grudge match on occasion, I dont see a problem with the 30 over NA.
PS: Next year I'll let you know how my NA holds up at 26 lbs boost.
I have 2 turbo blocks & am now building a NA with good parts like the others for my own knowledge. The KEY is NO (or very little) Detonation, but that applies to both of them! Mine are in the 600HP range altho, at 30 over, I would probably take the the turbo block. Just because its been engrained into my mind over the years I guess????? I would bet that at 500 HP & again No Detonation you will be fine. I race mine quite a bit but for a friendly grudge match on occasion, I dont see a problem with the 30 over NA.
PS: Next year I'll let you know how my NA holds up at 26 lbs boost.
jwillettgn
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I ask Ken Duttweiler about it when he was at Buicks at Bristol years ago and he said not to worry about using our 140 block. The way my son is on equipment I am sure he will give it a good testing. Hope to have it done this summer, of course I have been saying that for the last 4 summers. LOL
Garret, I plan on doing the same thing on a 85 t type to 86-87 conversion. I never heard about the deck heights being different, does this affect compression ratio at all? What is the difference in the water drainage? How did you plumb the oil return line, how did you mate it to the turbo, and where in the pan did you put it through.
differences
Yes it would raise the compression ratio unless you used a thicker head gasket like the one Cometics offer.
I was told that the 109 block has a water drain between the freeze plugs.
I mounted a #10 AN fitting in the passenger side of the oil pan-forward. I then ran a 3 foot section of push lock hose to the underside of the turbo. The factory 87 oil drain is made of a steel flange and an aluminum corregated tube. I cut the flange from it and had it welded to another #10 AN fitting. I then pushed it into the push lock hose threaded it onto the AN fitting. I then bolted it up as normal. Everything was available from Jegs or Summit. I can email pictures to you of the parts, but I can't seem to format them correctly for this web site.
Yes it would raise the compression ratio unless you used a thicker head gasket like the one Cometics offer.
I was told that the 109 block has a water drain between the freeze plugs.
I mounted a #10 AN fitting in the passenger side of the oil pan-forward. I then ran a 3 foot section of push lock hose to the underside of the turbo. The factory 87 oil drain is made of a steel flange and an aluminum corregated tube. I cut the flange from it and had it welded to another #10 AN fitting. I then pushed it into the push lock hose threaded it onto the AN fitting. I then bolted it up as normal. Everything was available from Jegs or Summit. I can email pictures to you of the parts, but I can't seem to format them correctly for this web site.
