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Gearing choice for engine build

2K views 19 replies 3 participants last post by  prostcelica 
#1 ·
Im am just putting the finishing touches on om SBC 355 build. I have a ford 9" with 355's in it know. My cousin has a set of 411's he offered up to me for free and I was wondering if I should take him up on it or should I stick with what I have. It is a weekend street car. Car weighs about 2500 pounds
Thanks in advance guys

SBC 355
Stock but fresh bottom end
Edelbrock Estreet heads (ported)
Edelbrock air Gap
Comp XR274R solid roller - 236/242 @50
Recomended Springs/retainers and keepers
Crane/Scorpion Full roller rockers 1.5ex/1.6in
Holley 670 street avenger
MSD street fire dist./6AL box
Standard 4 speed Saginaw (until it goes boom:))
 
#3 ·
Its not a race car but might take it to the track once or twice a year but mainly a street car. Unfortunatly it is just the gear set and not a 3rd member so I cant just swap it out easly to try it. The intake is an edelbrock air gap and the exhaust is 1 5/8 shorty headers, 2.5 inch through maganflows. I was thinking od adding electric cutouts just for fun:)....So Vin your saying if its a street car stay with the 355's??

Hey Fbird I hear ya on the carb. Ive already been shopping for something bigger. I just have a 670 sitting on the shelf......maybe ill just leave it there. Tires are 295/55/15 mickey thompson drag Radials. Thanks for the heads up on the lash settings. I think I saw somebody else on the site recomend that as well in a previous post
 
#5 ·
I use a 3.50 gear and its good.If I was drag racing I would gear the car for it to be at or just under redline in mt finishing gear. In my case fourth and still have O/drive to tolerate street driving
If the car leaves hard I would think theres daylight under the front tires for a short time
 
#6 ·
I want to try and get the best of both worlds. I will say that with the old motor which was pretty well a bone stock sbc 350 with performer intake, that holley carb, humps, headers and an "RV" cam cruised at around 2500-3000rpm at 100KMH and hit pretty hard of the line. Any idea what the highway speed woud be with the 411's knowing that the 355's ran around 2500-3000??
 
#7 ·
Thanks for the feed back Vin. I think what ill do is run it with the 355's in it at first and see how it is. If its a total dog off the line I can go to the free bee 411's. I just wanted to ask you guys to see what everyone would say. If everyone came back and said "it will be a total slug off the line" I would do the gear change now but it seems like im in the ball park with the 355's.

On a side not any guesstamations on 1/4 mile ET's??
 
#9 ·
over 120 mph is a high 10 second car. Ive used gears from 2.73 -- 5.57 on the street.My big block Camaro had 3.36 gears and on the high way I felt the gearing was a little steep for long trips,and it destroys gas mileage. I drove my old 67 Camaro from Vancouver Canada to Bremerton raceway Washington state,,60 mph equalled 3.700 RPM on the highway for 2 hours, 3 hour trip took 4 hours
 
#12 ·
Im in Nanaimo but Im just starting to get into racing but my family is into pretty huge. They are always over on the mainland racing. Mission, ashcrost, etc. if your into racing you may know them. My uncle had a burgandy chevy II with "MID LIFE CRISIS" on the side. My cousins have a Yellow S10 with a big block, Green Vega and a Beretta door slammer with a blown hemi. Ringing any bells??
 
#14 ·
LOL!! sounds good. Were do usually race?? Also....I hate to ask but im going to anyway:) What kind of HP/TQ #'S do you think that combo of mine will make? And any suggestions on things to improve?? What do you think about the 670 carb ? Also, I had a H pipe in my old exhaust system. I am going to re-route the exhaust and am torn between an X, H or no cross over pipe at all. Any thoughts on that??
 
#15 ·
I am using shorty header as Im tight for space. I know i could build a set of long tube but when I originally built the car and wanted to get it on the road so I picked up a set of shortys for cheap. The car is a 72 celica with fabricated tube frame. You are correct about the 500' track outside vic but this is street that will occasionlly go to the track so Im wanting to get a gear that will still hit hard but wont be a total bear to drive on the street
 
#18 ·
WOW!!!! Why dont you tell me what you really think. Im asking because I DONT KNOW. isnt that what this forum is all about?? I am jsut trying to figure out how much is to be lost. If I go by your theorys id be into this motor for 25k. If you asked me a question I thought was "not rocket science" I would never speak to you or anyone that way. I would answer and try and be as helpful and friendly as possible. Im embarrassed to call myself a canadian.
 
#19 ·
exact header tube size and length is hard to determine. similar formula as an intake manifold except the other end.
A 4 into 1 header is like a single plane intake,it will make more power at a higher rpm than tri Y headers.Try Ys act like a dual plane with the bottom end increases starting at a lower rpm and rolling off peak powers sooner.
Tube size,smaller tubes scavenge the head sooner but will not have enough volume at higher RPMs or on bigger displacement engines.
some engine builders will generalize and say you need 1 5/8 primaries for 375 hp or less and 1 3/4 primaries up to 500 hp,after 500 hp you might need 1 7/8 primary pipes.
this type of statement is ok at best,or a starting point. There are a lot of ponies left on the table because people buy a $200.00 set of headers that fit 5 different cars,then spend 10k on stroker engines with big cam/heads and wonder why there engine makes ok but not spectacular power

choosing perfect headers is very complicated and almost always over looked
 
#20 ·
Thanks for the great info Fbirb. I really appreciate it. This is my first engine build so im kinda learning as i go. I had no idea block huggers were such a power killer but know i do:) That is a good plan. I think i will cut apart my exsisting headers to make long tube. I have measuered the primarys and they are deffinatly 1 5/8 od. I have a freind that will most likley have a 750 he will sell or trade me for.

Again, thank you for the very helpful info.
 
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