Beob

Hey Guys, Just about to send in my 455 to be rebuilt. I would like to get around 450 HP. Im not sure what cam or pistons to use to achieve this. I plan on scraping the G heads and going with the Edelbrock aluminium heads. Ive been running solid lifters and roller rockers. What are some pros and cons of solid vs hyd lifters. Also can I reuse the old roller rockers. Any suggestions or advice would be appreciated. Thanks very much, Rob

joe_padavano

Here ya go:

http://www.popularhotrodding.com/tec...ild/index.html

Warhead

Send pic's of the G' heads!!!
Jim

cutlassefi

Yes normally you can reuse your rockers. Solid lifters are noisier than hyd but typically don't require the number of adjustments like they did in the past. Solid lifters will rpm higher, not an issue with a 455.

Texas Jim

Joe,
Thanks f/ posting that article from PopularHotRodding. I thought that I had found every article on the Olds 455 and especially PHRs, but I was wrong. I was happy to see an article where the 455 was put on a dino using the factory cast heads. This also showed that the 455 w/ factory heads can handle an 850 carb, a Demon no less. This article convinced me also to use a larger than stock pan, along w/ the oil restriction components that I had planned on using, even w/ the mild build. Thanks again, Joe. Along w/ the Olds Mod and Tuning Guide, Dick Miller's book, and this article, I have a perfect game plan f/ my reliable strong street motor.

QUESTION: The article read; '71 "C" heads. I have a '71 455, and my understanding was that the '71 came w/ "G" heads. Was this a typ-o in the article, or is the info I have flawed. Thanks in advance.

Beob

Thanks for the info guys, I will be selling the G heads in a couple of weeks.

joe_padavano

It's a typo. Your info is correct. C heads were only used in 1967-1969.

Texas Jim

Beob, Do you guys still have a Keith Black Engine Shop on Long Island? I remember in the '70s, there was one on Long Island. A guy I went to the track w/ , National Speedway and Raceway Park, had an injected 327 built there f/ a B/G Vega he ran. Good Luck w/ your build.

71 delta88guy

Go for the keith black forged pistons,edelbrock heads,port them either yourself or have a shop do it. Shave them to get at least 10:1.Get a cam to match the compression ratio and what you expect to turn the engine.Don't go too small or you will end up with too high compression and have ping issues. 520 ish lift,225 ish duration@.050 would be a fine starting area.Dual plane or medium riser single plane intake,Carb will depend on rpm use. Street 650,dual purpose-750,race 850.

Texas Jim

Spending all the money on aluminum heads, and everything else at that level, why put a 650 or even a 750 carb on it? You can run a 750 successfully on a mild small block. If you don't run an 850 after spending all that money on the other components, you just threw your money out the window.
I read afew weeks back, someone posted, a 750 may be too much f/ the 455, I thought it was wrong. I gave the benefit of the doubt, as I'm not an Olds guy and thought maybe the stock heads just couldn't take that size carb. Acouple of the "more experienced" Olds guys said that the 455 could take a 750 easily, and after reading the article that Joe posted the link f/, we see that an 850 can be used successfully even w/ factory heads. W/ aluminum heads, there are further options if you want.

70 cutlass s

I can add some to that Jim on the stock 75-76 455 with J heads. A 650 would work ok.
On all other 455's I would recommend 750. On a engine that being built like this no smaller than 800. So yes 850 would work fine. Fact is a smaller carb. will cost you hp on an engine built like this.

With the cam recommend a duel plane intake wouldn't be enough.

Beob

Thanks very much for the info, it will help. Ive been running a 750 dp carb on this mostly stock 71 455 and its worked very well. Was planning on having it rebuilt, but now may go with a new 850 dp. 10:1 comp and .525 and 225 dur cam sounds good thanks, Rob

captjim

This is just my opinion, based on experience and no real hard numbers, but I think Olds engines like big carbs. Maybe it is the small ports/high velocity, I don't know. My mild 355 has a 670 Holley and best ET was like 4 jet sizes higher. My 10.25 to 1 355 runs much better with a 750.. Again, just my opinion, but as long as you run a vacuum secondary style carb, better to go a little big. The smaller carb might make more low rpm torque and get better mileage, but will leave some performance on the table.

Also, don't get too hung up on HP numbers. What are your intentions for the engine/car?

71 delta88guy

The size of the carb would be dictated by the rpm use. Having a e brock headed 455 does not mean the person is going to run 5000+ rpm. My old 461 liked a 650 very much around town,highway cruising. When I beat on it there was a definite reduction in oomph. The 750 was awesome-relatively speeking when romping on it but around town /cruising mileage suffered. Just my experience.

citcapp

I run a 770 holly street avenger on my edelbrock head 455. Gives good performance at all rpm's. I don't check the milage as the car is my toy and did not build it with milage in mind. Will ugprade to a 850 on my 455 in the 48 due to a higher level of build.

dc2x4drvr

I've chassis dynoe'd my 461 with both a 750, and an 800 cfm Q-jet, didn't see a nickles worth of difference...now I'm going to super tune the 800 with a LM-1, and try the dyno again.

Texas Jim

I was going to say, who in the hell would by aluminum heads and run a small carb? To each their own. But 99% of the people who buy Edelbrock aluminum heads buy the appropriate cam, carb, etc. f/ performance purposes, and mpg isn't thought about much w/ a hi-po application. And a 455 built to that level would run way better w/ a big dp carb. I had mentioned weeks ago, that I ran Demons on worked 383 Chevys many times, and now I see that the link posted showed damn good results w/ an 850 demon. F/ quite awhile, Demons have been the one to run. F/ a hi-po build, just my opinion, a Q-jet just don't get it, and a 650 is a waste of time. I'll stay w/ a stocker if I'm looking f/ mpg, and not waste my money on hi-po components if I'm going to "granny" around.

ah64pilot

I'm sorry about resurrecting a dead post but how can you say carb size is strictly a matter of RPM? There are so many other factors that go into selecting a carb than just RPM. How about size of the engine, the lift of the cam, duration of the cam, size of the valves, how much the heads flow? I wouldn't be flaunting your experience when a guy says he wants to build a 450hp 455 and all you have to talk about is you putting around town.

Go for an 750 or 850 demon, but wait to decide until you know whether or not you are going to get Edelbrock heads, whether you have them ported or not, and what cam you are going to use. AND please, don't build a 450 hp engine and complain about "around town / cruising mileage". Ridiculous.

ah64pilot

PS...I have Keith Black flat top forged pistons - IC886 and Edelbrock heads. I shaved .006" off the block and am at 10.53:1 compression. If you shave anything, shave the block not the heads. Also, if you have anything close to what delta suggests for a cam there is no way you should even consider a 650cfm carb. At a minimum you should run a 750 on the engine he suggests.

71 delta88guy

Jeez. All I said was I use a 650 if I'm going to be driving locally or actually don't want to beat on the car. I did mention the drop off in performance when on highway at higher rpm's when using the 650. So what's the issue here? If you have an edelbrock headed big block you HAVE to use a 750 or bigger carb? I get much better driveability with the 650 and actually save some gas.When I take it to the track-yes I've been there- I use an 850 I got last fall.If you plug in a 461 to a carb size chart it shows there is no need for a big carb UNLESS you are going to spin it up into the 5000 to 6500 rpm range.Since I just don't do that very often I use the smaller carb.

ah64pilot

I apologize Delta, everyone drives differently and often times I forget that. I always want to have the ability to win should an impromptu street race arises. Different walks of life I suppose. Please excuse my earlier comment.

71 delta88guy

Hey. No problem.I LOVE to beat the ever lovin crap out of my super heavy weight. I just try my darndest to save what gas I can and of course the $$ along the way. When it comes time to rip;lets go.Have a great time this spring/year.I'm going to try to get this 5000 pounder into the 12's