I have a 1993 5.0HO and recently blew the engine. I swapped it with a 1988 5.0 (supposedly from a thunderbird...) and the car doesn't seem to have liked it. I'm getting backfires in the intake. I think it may be a timing issue.

So first off, I was wondering if a 5.0 with "EFI" written on the intake (1988 engine)is the same as one with "H.O"?

 

EFI: electronic fuel injection
HO: high output
either of those two motors will be both...
does it run, or just backfire? You might have set timing with #1 cyl on the exhaust stroke

 

Just cuz it's EFI doesn't mean it was an HO. I'd make sure that the 5.0 you put in is indeed an HO, because if it's backfiring through the induction it sounds like you have an HO computer with a non HO engine or vice versa. But yeah, make sure you set timing on compression and not exhaust

 

An '88 tbird 302 would be a HO. However, it sounds like you're not sure. EFI is just fuel injection, it came on all 302s in that year range. The firing order on a HO is 13726548. Non-HO is 15426378. Figure out which one you've got and you'll know. I'll let someone else chime in on the computer thing, I'm not familiar with them

[Firewall]
4 8
3 7
2 6
1 5

 

Running a Non-HO motor with an HO computer shouldnt be a problem should it???

 

yes yes it does, since the HO computer will tell the injectors to fire at the wrong time

 

Just curious but isn't a 88 engine set up for speed density and the 93 that your putting this engine in is set up formass air ? I'm sorry if this sounds like a stupid question but I know that my 88 is speed density and I thought that from 89 up everything was switched to mass air. Not sure if you switched it over or if it evenreally matters.

 

engine wise... SD or MAF doesnt matter

 

sounds to me like a 1-5 firing order motor swapped into a 1-3 firing order car.

time for a cam swap

 

O.K. thanxs for clearing that up Adder!