I Finaly got my 68 firebird and after driving it 10 minutes it threw a rod. I purchased a 455 and am haveing a problem and i cant find any first gen sites.

The engine I got is a 455 from a grand prix with 7m5 heads. Well I got supercomp headers And on the heads I have there are 4 bolt holes but the headers have 6 bolt holes the ones that aren't used on the headers would be both outside bolts. If I didn't use these bolts since there are no holes would I have any problems or is there something I can do to make the headers fit right. IF any one knows of a website or a way i can make something that will work.

 

eeither get new heads or tap the ones you have. what year the 455? 6X-4 will raise the compression on the 455 to about 8.0-1. they also have the hardned exhaust valve seats for todys poorer quality gas. AND they have 6 exhaust bolts.

 

Okay,

First off, why are you putting a 455 in a 68 Firebird? In 68 Firebirds came with 400's not 455's the engine cradle is not able to handle the horsepower and torque(roughly 425hp/550tq. depending on year...) of a 455. You may end up twisting the frame of the 68. Also there is going to be less room in the engine compartment so it will be harder for you to change plugs, wires, ect... Headers, you have the wrong headers, most likely those are Chevy 454 header and they may not and or will not work. Check your PORTS on your heads to see if they match... Oval port headers will not match up o D-port heads... and vice versa... if youe can use those header not using the outside bolts may risk warping the flanges on the headers creating leaks... Hope this helps you... If you have any other questions feel free to email me....


Rob
fiream@yahoo.com

1976 Pontiac Firebird Formula 400
1983 Pontiac Firebird 2.8L 60 degree V6

 

ITs all from a 72 see i dont want to get rid of the heads because of the head work done to it and it has 12:1 compression. it has over sized valves port polish.

 

I wanted a 455 because i plan on raceing that car. a 455 block is the sam as a 326 a 350 and a 400 everything is interchangeable. The headers are for a pontiac with D port heads which i have its jsut the 2 end flange blot holes. i was thinking of some kind of bracket but still cant come up with a idea.

 

don't worry about the heads here are you head specs.
Year(s) App. Prod. # Original part# Head Cast# Valve Sizes Stock C.C. NHRA min C.C.
1972 455 494498 486075 7M5 2.11/1.77 114 101.8

 

455 is completely different from a 400

 

its the same block tho only difference is different bore and stroke. alll my old parts off the 350 would fit on my 400. everythign is identical

 

correct, main diffs between 400 & 455 are the internals. The outside diminsions are virtully the same, if there are any differences at all. And all headers you can get will have the 6 olt pattern. You hae pre smog heads on. hopefully they have been rebuilt. What engine was origonally in the Firebird? If 8cyl, take all brackets & accessories off old engine & transfer to new to keep alignment If new engine has all accessories, you're golden

 

WTF?

Ok, first - DO NOT GET RID OF THE ENGINE IN THERE CURRENTLY (with the blown rod) Could be a Ram Air 400. And regardless of what ANYONE tells you, the only things you could NOT use from this blown engine, onto the 455 is basically pistons/crank. Pontiacs (and no, they are NOTHING like Chevy's) are SUPREMELY interchangeable!

Website? There is only one. Join us @ http://www.classicalpontiac.com. Myself, Todd, Old Man Taylor, Cliff.... man, there is simply the greatest concentration of Pontiac knowledge on the planet in that Q&A forum.

455? Run a set of 6x-4's (I've got a set if you need) will yield more like 8.5:1 compression, run like a 744 OEM style cam (or perhaps an 041, if you've got the gearing for it!) and you'll be set. 455's long stroke will fry tires like no tomorrow. Head to that site, and you'll be set man!

 

THIS IS SO SIMPLE TO SOLVE.
FIRST PHONE THE HEADER MANUFACTURE ASK THEM
NEXT ASK THEM FOR THE SOLUTION!

The was original block is/sounds pretty trashed.
I do not know if it's a true 400 mill that was destroyed.

I wish I could have been on the maiden ride!
I love hearing BOOMS as I've done them myself!

All that matters is to insert & hold down the motor, then hook up exhaust.
The exhaust pipes go in first, then lay motor ontop.
IF they Hooker SuperComps, Hooker is in Ontario, CA.
Find part number on the tube, have paper & pen ready along with the type of heads used & the exhaust bolt pattern.
Call them for tips.
Simple.

 

I called Hooker and they said that i would have to have them tapped so i could use the other bolt holes. so im going to take them to a mechene shop and have that done i pulled the heads off tonight. Now i gotta undo the tranny so i can pull the enigne out unless someone knows how to pull the engine with the torque converter still on. This is a fun project. The engine in there now is a true 350 with 350 2bbl heads code 13 . I dont think the block can be resused im p finding chunks of metel everyware i dound the bolt to my connecting rod it put a small dent in the crossmember under the enigne.

Karl i will be out in the valley tommorw if you want to help or come see it. If you come wear crappy shoes i pulled the tranny dipstick out and lets just say tranny fluid is everyware and every step you take you slip. Also if you have a Big jack i can borrow that would be great my 29.99 AZ POS dosent jack up the car too high. Oh Karl email me your phone number again Aol deleted the email you sent me.

 

Wanna sell those #13 heads?

 

Yah let me pull the heas when i have the engine out to make sure nothing happend to the valves when the rod went. Email me about them.

 

Was the original engine a pontiac 400 or a pontiac 350? Did the rod put a hole through the block?

 

In accordance with Brad's announcement at the top of the board this post has to be locked.


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