hot air intake on a (109) BLOCK?

[BLACKHAWK38]

Since the deck height on the hot air blocks and the intercooled 109 blocks are different by .030 or so, Will a hot air intake bolt up OK to the shorter deck 109?

Regards

 

[cool 84]

It'll bolt up fine. If it worries you, use the composition headgaskets which will make up the difference.

 

[TRiv]

I agree, if an 86-7 manifold bolts up to 84-5, then the opposite would be true. I have an 85 and 87 manifold on bench, measured the lower flats closest to lifter valley and the width is the same, of coarse the angle of the flats that mate with the heads are the same, so it sure looks at least the mounting sufaces are identical. I am guessing you are looking to solve anouther problem rather than looking to mount an 85 manifold to 109 block ?

Unfortunately I don't know all the ins and outs of these engine yet but, what about head bolts, if heads are reinstalled after machining block do you have to use new ones? I thought I read that somewhere but not sure. is that spec to 84-5 and or 86-7 shortblocks? Something about the torque, just don't remember.

On a better note, while waiting for the rest of the 87 conversion parts collection found something that us Riviera owners may be able to do. Unlike the Regals our turbo hangs off the back of the block, well I have mocked up on engine stand the 87 manifold with the turbo in that stock location and it sure seems with the exception of a little fabrication, the turbo Rivs can use the 87 manifold without having to convert everything over. Well it's still not intercooled but we can use the better manifold, and the turbo out can be plumbed to have the output entering the top of the 87 manifold, straight , even shot to all 6 runners (kind of like the 83 pace car). I'll find out more details.

 

[Chris Brooks]

109 block

I have a Jack Merkel built shortblock. Its a 109 block with stock heads and stock hotair intake. As long as u use 86-87 headgaskets everything will line up. Just remember to put a plug where the 86-87 oil return is in the front of the block.

Chris

 

[racemybuick]

got a 109 in my car

My car came to me with a hot air set up and a 109 block underneath. As I understand it, there is nothing to change as per mounting. Just that drain plug. In fact, I am purchasing another block soon, so i can get a numbers matching car back together. If anyone is looking for a 109 that will need to be rebuilt, let me know...i'll probably be pulling it in a month or so.

good luck!

John

 

[6SENSE]

I know of at least one hotair GN around here with a 109 block.

Heads are the same between years. 109 block is decked more, thus the reason for factory 86/87 headgaskets being roughly 3x the size of 84/85s. So, if you go with GM headgaskets, use the 86/87s, as already mentioned above (unless you want a big bump in compression). If going with aftermarket headgaskets like the Felpro1000's you would get a slight bump up in compression anyway, just not nearly as bad as using the skinny factory 84 steel shim gaskets (thats why you hear of 86/87 guys using TWO steel shim gaskets stacked; unless your REDS ). Id go with the GM 86/87 or the Felpro1000s, just my opinion.
Oh, and of course youve got the oil return hole on the front of the block, as also previously mentioned. It will wind up behind your AC compressor/Aternator bracket.