400 vs 455 - Pontiac GTO Forum
Nov 10, 2011 · So when I start looking for parts, I would like to know if I am limited to just Pontiac 400 motors or if I can use parts from any Pontiac engine (350/400/455). Any advice would be helpful. P.S., regardless of the answer, I am still going to get this '68 400 YS code block if …
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 …
Help with ID and estimated HP of a 455 | Pontiac GTO Forum
Jul 7, 2022 · All blocks were stamped sequentially in order of engine build at the Pontiac engine plant. Prior to 1968, the EUN was used for warranty purposes. 1968 and up the VIN was used for warranty and the EUN was for factory engine recalls or other maintenance requirements. Your block was number 61,672 from the start of 1973 production or early September.
70 455 Engine Timing - Pontiac GTO Forum
Oct 11, 2016 · Retarding timing makes an engine run hot. Advancing the timing makes the engine run cooler. The stock timing for the '71 455 HO is 12 degrees BTDC, the 1970 RAIV is 15 degrees so 16 is in the ball park. I attached the distrib/timing specs from the 1968 Pontiac Service Manual just for example.
Timing adjustment - 455 pontiac | Pontiac GTO Forum
Jan 8, 2018 · Im rebuilding the 455 and now just adjusting the timing, The car is for street strip, edelbrock intake , long tube headers, a big cam! I set the timing to 14 initial timing and 36 total timing. Should i set it the same or maybe lower it to 12 …
YC stamped engine in 1970 GTO? - Pontiac GTO Forum
Mar 18, 2015 · The YC code was found in only 1 book (which is basically a Pontiac "bible") that I have while the YC code is listed as a 1971 455 engine. The 455 is called an HO engine in the GTO where 71 and later had both a "standard" lower HP version or the higher HP "HO" engine with the aluminum intake. Heads are#64. Full casting number is 9799364. I have ...
455 Casting/Block codes - Pontiac GTO Forum
Jun 14, 2013 · The YH is the engine code that, along with the block casting number and the casting date, identifies the block as a 1970 Model Year high-compression 455 for full-size cars. As far as I know, those were originally built with 2-bolt main bearing caps.
Pontiac Magazine 560HP build-up - Pontiac GTO Forum
Aug 7, 2011 · The 455-cu.in. V-8 debuted in 1970 and was the largest displacement Pontiac engine ever built for the street. It is likely also one of the best, said Jim Taylor, the legendary Pontiac engine builder from Phillipsburg, New Jersey. "I love Pontiac engines, and the engineers who built them were tremendous, absolutely at the top of their game," he ...
428 vs 455 - Pontiac GTO Forum
Jan 21, 2024 · From out dyno days we see no horsepower difference between the 4" stroke 428 and the 4.21" 455 engines. You just turn the 428 about 400 RPM high and horsepower will be equal if other parts of the builds are the same. What we do see is a pretty good kick in torque with the 455 over the 428 and just no getting around that.
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.