455 engine and parts for sale - Pontiac GTO Forum
Dec 15, 2021 · This posting is for a Pontiac 455 engine, 4 Speed M21 Muncie Transmission, Hooker Super Comp Headers, Holley Carburetor and High Torque Starter all of which are out of my 1970 GTO . Engine was running strong with no issues when pulled. Engine has somewhere between 4k to 5k miles since rebuild.
4 BOLT 1971 Engine Project - Pontiac GTO Forum
May 31, 2023 · the 483677 455 block was first cast in early G (July) of '70. All the very early 483677 455 blocks were used to fulfill early '71 455 D-port engine builds (YC & YG codes). These will be drilled & tapped for four bolt mains, but nearly always will have 2-bolt main caps. Many years ago, I had an early G dated YG that had factory 4-bolt caps.
1970 GTO 455HO YH Engine / 64 Head Casting - Pontiac GTO Forum
Sep 25, 2012 · I recently purchased a 1970 GTO 455HO. I have been investigating the build details and am a bit stumped by the YH engine and 64 head combination in this car. I have a visual inspection of the the block and heads to confirm the numbers, and dealer order documentation say it is a "4 BBL 455 HO" option code 344.
1970 455 questions - Pontiac GTO Forum
Mar 21, 2017 · the most common Pontiac 455 for '70 models was the YH engine with 15 casting heads. This was the standard equipt engine for '70 Bonnevilles. Pontiac built a TON of '70 Bonnevilles, & only a few received the optional big valve 64 casting headed XF engine. Most of those were XF's & went in '70 GP's.
Reference: How to identify your Pontiac Engine.
Aug 19, 2022 · For example, the engine in my '69 carries a date code of K278. K=November, 27, 8 meaning 1968. This brings us to another fact you must consider when interpreting date codes. The Pontiac engine foundry would begin casting parts …
400 vs 455 - Pontiac GTO Forum
Nov 10, 2011 · So, at equal displacements and especially these days with several choices available in aftermarket cranks for both 3.000 and 3.250 main blocks (in the same stroke), the only difference between a 455/461/462, etc built starting with a 455 block and a 455/461/462, etc built starting with a 400 block is going to be the size of the main journal ...
455 value? | Pontiac GTO Forum
Feb 24, 2016 · 485428 455 blocks were cast from late Nov of '70 (for '71 model use) up through the '74 model year. What pair of heads is on it, along with what the two letter block code is, can have a big effecton what the core engine is worth.
Engine Help ...455 | Pontiac GTO Forum
Mar 26, 2013 · I am trying to determine the compression ratio on my '69 GTO. It has a '74 trans am 455 engine. I saw 6X casted on the side of the heads. Are 6X heads standard on the '74 455 or are they after market? How do you measure the stroke?
compression - Pontiac GTO Forum
Aug 15, 2016 · Compression test needs to be done warm engine and all spark plugs removed. Spin engine over through 5 compression cycles before doing test. 8.2 - 9.2 compression engines - regular fuel. 150-170 PSI @ 155-165 RPM's 10.5 - 10.75 compression engines - premium fuel. 185-210 PSI @ 155-165 RPM's
Pontiac 455 intake manifold gasket - help!!! - Pontiac GTO Forum
Aug 17, 2020 · hey , rebuilding my 455 and all the gaskets seems to go on right with the felpro 2806 kit i bought except the intake manifold gasket. the middle port seems to be too big compared to the stock gaskets that were on? its opening up both passages at once? ill ive attached some pictures of both the gaskets , is it the wrong one? could anyone advise on …