Double D racing Posted March 2, 2013 Report Share Posted March 2, 2013 i got this truck in a trade...its got throttle body injection,(fuelpump in gas tank)was gonna switch out distributors. go to an HEI distributor since i have a whole shelf full of em.it was runnin a little rough,i noticed the pickup coil looked like original stuff,little bit loose around the base,well the kids took it out in the pasture for a few laps and now she wont fire.assuming the coil or the module went out....can i jus stab an HEI in there or is it a little more complicated than that ??? eventually was gonna take the throttlebody off also...ole truck gonna jus be a parts runner/field hopper anyways..... Link to comment Share on other sites More sharing options...
JamesHigdon Posted March 3, 2013 Report Share Posted March 3, 2013 My experiences with the TBI motirs are a little more limited but I believe the TBI system picks up its cam signal from the distributor so no you can not drop an HEI in and keep the TBI. You can switch out both the TBI and distributor but one or the other and it won't work. Link to comment Share on other sites More sharing options...
jwmbishop Posted March 3, 2013 Report Share Posted March 3, 2013 James is correct on this! I had an 87 and switched to carb and hei just for that reason. Link to comment Share on other sites More sharing options...
flyingaces Posted March 4, 2013 Report Share Posted March 4, 2013 Danny, these are all corrrect. the cam sensor is in the dist. so it wont work. Link to comment Share on other sites More sharing options...
Double D racing Posted March 5, 2013 Author Report Share Posted March 5, 2013 gosh darnit...so if i change out intake and distributor then it would work??? Link to comment Share on other sites More sharing options...
tps48 Posted March 5, 2013 Report Share Posted March 5, 2013 I changed one out a while ago, the holes to bolt the intake to the head have to be slotted ,but it's not too much trouble. Link to comment Share on other sites More sharing options...
jwmbishop Posted March 5, 2013 Report Share Posted March 5, 2013 so if i change out intake and distributor then it would work??? Yes - but may be easier to run a two barrel adapter - I am thinking there are adapters from TBI flange to the 4412... Not 100% sure though... underhood clearance is not an issue - but linkages MAY be. This way you also retain the vac ports for the evap etc. I changed one out a while ago, the holes to bolt the intake to the head have to be slotted ,but it's not too much trouble. That depends on the intake. Many now come with slugs for the bolt holes that interchange to match both bolt patterns (dual fit). Some of the 87s also still had the early head anyway! The 86 all were late one piece seal block with early heads (thats the way I built my 383), the 87 saw the new heads in most applications - TBI is almost always late heads.. the very rare carburetor version (heavy truck) used the early heads. 87 was the last year of those. The indicator will be valve cover - if cover is held on with perimeter bolts any early manifold will direct fit. If the valve cover bolts go through the cover (center bolt) you will need a dual fit manifold. There are a ton of knock off clones for AirGap etc on Ebay that are dual fit and if installed with care are quite functional (and even have both square and spread carb flange surface - but be careful - the walls are quite close when running a square on some of em) - just make sure everything fits right before you bolt it all together! Slotting the holes in an early manifold - It works - but its not the best way. the angle of the bolt is what changed (center of holes is in same location at head manifold surface) so the boss angle is off meaning the bolt does not seat flush all the way around... that stresses the bolt under thermal expansion and can break em off flush with head! If you then also spot face the boss to correct the angle - the material gets quite thin. Also when slotting - the bolts now pull downward more than sidewards - this means you can crack the manifold very easily if there is not enough end gap (oil valley ends front and rear) to accommodate expansion under heat - as well as change the distributor depth mis-aligning the gear! I believe there some slug kits available that allow you to simply bore the bolt bosses out - the slugs then make the angle change. I have no experience with them though - but it seems that if you do not have a way to make the rebore the correct angle you end up right back with the same issues! By the time you consider all of this - and the cost of proper machining - that 100 dollar ebay manifold is looking quite attractive! Link to comment Share on other sites More sharing options...
JamesHigdon Posted March 7, 2013 Report Share Posted March 7, 2013 There are TBI intake flange to 4412 (square bore two barrel) adapters. Keep in mind you will also likely need at least a fuel pump pushrod if you plan to run a mechanical pump and some TBI cams didn't have any fuel pump lobe at all. Link to comment Share on other sites More sharing options...
Double D racing Posted March 8, 2013 Author Report Share Posted March 8, 2013 almost forgot about that one.(fuelpump).i found another motor to install.jus gonna get rid of the whole headache....truck jus has too many issues for injection and computer...gonna do old school Link to comment Share on other sites More sharing options...
jwmbishop Posted March 8, 2013 Report Share Posted March 8, 2013 There are TBI intake flange to 4412 (square bore two barrel) adapters. Keep in mind you will also likely need at least a fuel pump pushrod if you plan to run a mechanical pump and some TBI cams didn't have any fuel pump lobe at all. Yea - good catch! The 87 350 4-bolt block I used did not even have the boss machined thru for the push rod! I went with an inline electric when it ran in the 87. Of course now moot since the engine is in my 57 and injected with an MSD Atomic EFI (with timing control) and supplied by an in-tank return less pump. Link to comment Share on other sites More sharing options...
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