Blown head gasket. Bummed

[PETEGN]

Took my 87 out for a ride last week, punched it at 70 mph and it sputtered and made backfire under the hood. Knock was 7.1 on scanmaster. Runs great at normal driving. Checked under hood and all looked ok. But have been having a problem getting boost to stay in one spot. It seems like i have to keep cranking it up and up to go up. Thought i had it set at 27 with alky but i took it out today to try and trouble shoot itand it went up to 40 and blew a head gasket with no knock.. Had the feeling this was going to happen with the boost all over the place. Can anyone tell me why the boost wont stay put where i set it?.
Now i got to rip it apart and fix it. It is a street car which just goes out on the weekends or an occasional long drive. Now that its apart should i opt for aluminum head or have my origs rebuilt? Probably should put headers on it while its apart. The car has about 57,000 miles on it. Should i change the timing gear and the oil pump? Anything else i should do while its apart? Cam? Etc. If iam going to have to do all this work what should i do to get more hp.
Sorry for the long thread. Had a few beers to drown my sorrow.

 

[PETEGN]

anyone? please help. thanks

 

[bmackinnon]

ummm... obviously the wastegate is sticky/sticking/stuck??? what kind of dp/gate??? if it's an internal style gate, pull the rod loose and see if the flapper arm is stuck/sticky.... if it's an external gate.... others would know better...

stock headers have runs 9's.... probably faster..... so..... ???

timing set would depend on condition... guess you'll be able to more accurately determine the need when you get it apart....

doesn't appear your mods really warrant a big $$ set of aluminum heads... a decent refurb/mild port might be more bang for the buck???

if the oil pressures (idle/cruise/wot) were good before, I wouldn't mess with the pump...just a thorough bottom end cleaning..... clearances on the oil pumps are critical with our cars, and if you don't REALLY know what you are doing setting up the pump, you'll likely be worse off than when you started...

don't sweat it... 40 lbs??? it could be worse!!! just my thoughts....

 

[PETEGN]

Hi Brian, thanks for the info. i have a gn1 down pipe with external waste gate. i was reading where you need to grind the hole bigger where the down pipe flange meets the waste gate. heard of that? should i just purchase a set of cast champions and be done with it/. thanks again, pete