Offy 3 vs. OCZ 2/4V

[schaferstephen]

Question yall. I'm pretty sure that in this case, the OCZ will outperform the log heads regardless, but let me just throw this out there.

Goals: Street car. Is not gonna see a track, probably not a quarter mile unless... Well maybe. haha. I don't need a fire-breathing hotrod, but I do need something that's gonna be fun to drive. Spirited street driving I guess is the word.

Having said that.. Power comes out of the head and the stock log ain't cutting it. I don't want to pour a ton of money into this, and for that reason I'm leaning towards the Offy 3 carb setup - I already have 2 Autolites, and the complete setup would be cheaper than an OCZ (or CI) head. I can get a reworked '82 250 head from O'Reilly's for about 300, or cheaper if I'm patient and find one in a junker car. Realistically speaking, how much power can I expect from a tri-carb setup on a modified 250 head? I mean a good port and polish job, have it shaved to keep the compression ratio, engine will get cammed and I'll definitely put an ARP bottom end on it. What type of power/reliability am I looking at with such a setup, comparing the Offy intake and modified log to an OCZ head with either a 2 or 4V carb? Which would be more streetable? Which makes more reliable power? Etc. What do yawl think?

Thanks!!

 

[CobraSix]

Funny you should ask:

http://www.kastang.info/ozversusoffy.html

It's a little outdated, in that the Offy's are becoming harder to come by than the Oz250 set up, but the performance observations are still valid. Remember, only testing was done with a highly calibrated Butt-o-meter.

For what you are looking for, I would recommend the oz250 set up, or CI's ALuminum Head, depending on how much you are looking to spend. Replace the stock cam with a 264 from CI, put the Oz250 set up on there (with a 4V like Kstangs, not to be confused with my Kastang) with a direct mount 4V Holley, and you'll have some fun.

 

[schaferstephen]

Aw man that's perfect!! Thanks so much

 

[FalconSedanDelivery]

A little more to it ,first automatic or stick ?, an automatic will require a loose torque converter , and then some extra cooling ( trans cooler ) not too big a deal with a 250 as they are the same as a SBF, but its still more money , a stick can get away with more mods for less ,but even then figure 200hp as the most for a street able combo in a log setup , I did the / have the log because at the time I started that was all that was available , If I was to start now KNOWING what I do , Id go straight to an OZ or CI aluminum , My combo makes maybe 215-225 , but at 12.3-1 its NOT a Daily Driver, low 14's at over 91 in the 1/4 is good but it was in a Very light car that was Race only ,I have Time slips and 35+ years of Playing with Hot Rods not a Butt-O-Meter , still it will cost 2-3 times the money to get the same as if you had a SBF289-302-347) combo , its your money , and the six is cool , but in the end you decide

 

[schaferstephen]

Right now I have a C4 but I'm wanting to put a T5 in because I really want a stick. If I can get close to 200 hp I'll be stoked, I figure right now I'm probably getting about half that to the wheels. The CI head would be awesome but man... I really really like the way the Offy looks, haha.

 

[Invectivus]

I feel it comes out to money. Log heads can be gotten cheap, but you need to do the work yourself to really save over the CI or OZ head. I'm working on making a dual 5200 C9 head because I have a buddy with a shop so milling/hogging the log will effectively be free. I'm going to practice porting on my 170 head, then clean up the C9 bowls and flashing. Here in Northern California, it would cost 6-9 hundred to pay someone else to do it, and with the extra cost of more carbs, plus the offy kit (or tons if research and fab time/costs for custom), plus added tuning complexity, you're around the cost of the CI head. You just don't need to write a check all at once. The CI head is far easier and faster to install and work with.

 

[FalconSedanDelivery]

Right now I have a C4 but I'm wanting to put a T5 in because I really want a stick. If I can get close to 200 hp I'll be stoked, I figure right now I'm probably getting about half that to the wheels. The CI head would be awesome but man... I really really like the way the Offy looks, haha.

If you do decide on the Log I have some suggestions , ( things I know now that I didnt the first go around )and a T-5 is THE way to go

 

[MPGmustang]

all good and correct, the i6 is not a power house, it's a work horse. it's meant to 'puht puht' round town. and to get more than 150hp out of it the cheapest solution is the Alum head from CI.

so just for a quick reference, I spent close to $1500 over time on my cast iron 78 large hex log... I should have waited and gone for the alum. even now I'm thinking I'll go for the Alum head as I want more power... in the mean time I'm tweaking my rear gear.

Now on the other hand, it's even cheaper to get a v8... but it's up to you. I personally don't have anything against any engine, except the i6 isn't fast enough (yet) I will probably stay with my combo for a while until I find a good enough excuse to get the alum head.

 

[schaferstephen]

In response to what has been said, one of the reasons I'm a fan of the Offy setup is that it will be cheaper (for me) than a CI head. I already have 2 of the needed carbs, and a friend of mine can do all my headwork for free. (And by free I mean I pay him in beer and BBQ Or like Invectivus said, I could practice port work on my 200 head, then do it for reals on the 250 head myself. Either way.. I'm in no hurry so I'm hoping to find a 77-83 250 head in a junkyard - worst case scenario is I get a reworked head from O'Reilly's for 300 bucks, but that's more than I'm hoping to spend.

After reading KaStang's posts, I'm more sold on the Offy setup just because from what I understand, it seems that at the cost of more complex tuning, I'm going to get better fuel economy around town and not miss anything on the highway with WOT. Also... man it just looks cool as hell. Probably will be a little more difficult to set up but meh if I was into doing things the easy way I'd never have bought a 65 mustang!!

@FalconSedanDelivery, if you have any advice about the log heads, let 'er fly!! I'm pretty certain that's the route I'm gonna end up going.

Also if anybody happens to have a T5 for sale, holla at me!

 

[CobraSix]

OZ head and T5 is a great combination. Actually, a T5 and an upgraded cam really wakes up the car. Oz or Offy is just gravy after that.

 

[MPGmustang]

simple and cheap... IMO... for the best buck.

c4 rebuild or t5 swap
offy 3x1bbl
cam with 274 duration and 112 lobe separation.

I say the c4 because it is a good trans, just no over drive. but one can compensate for lower RPM cruise with the rear gear and bigger tires.

 

[schaferstephen]

What type of cam would yall recommend for me in this case? Assuming that I cam it when I have a T5 installed and have the Offy intake installed.

I do like the C4 just because I'm sure it will last me as long as I want it to, but I am (hopefully) gonna be taking some road trips and I would kill for that overdrive gear. Also I really really love driving stick shifts.

As far as the rear goes, what should I do to build it up? Are there any 4-lug 8" rears? I have nothing against putting a 5-lug rear in, but I'm not sure if I could handle bigger wheels without rolling the fenders, and it would look funny with 5 lug in back and 4 in front. What yawl think?!

 

[bmbm40]

I like the Offy looks but often thought two carbs would look great and perform almost as well, like the path Invectivus is on. Two progressive Webers might be good. If you have a friend that does machine work you might consider this with your two Autolites although sealing the original carb hole might take some doing. If you use the head you have now it would be real cheap. Your machinist friend could probably have the head done in a few days. Just pointing out options, I like getting things done inexpensively. A little porting/polishing and the right cam and headers of course. It would be nice to hear some opinions from experienced members on how much power you might get from this. If you are getting 80 horses to rear wheels now and this will get you to 130 or
more thats a big increase. Along with a t5 a whole different driving experience. At least enough for fun, spirited driving.
If you decide it's not enough you could probably sell the log head for more money than you have in it and buy the CI head which is the final solution really. At least this way you are enjoying an enhanced performance level in the meantime. I can always recomend the 250 block. That little extra torque from the additional 50 cubes gives me that nice warm feeling inside. I have many thoughts on this because a 65 Mustang is at the top of the list for my next project and probably a warmed over 250 with a T5 or 4 speed auto/overdrive drivetrain.
In my Bronco a 5 speed trans was a performance upgrade. Yards must be full of T5s and with some careful parts gathering could be relatively low cost.
With enough time 250 heads or complete engines will turn up, definately check the yards often or car-part.com also.

 

[schaferstephen]

Hmm tbh, I've never even thought about a dual carb setup, it would be cool! I will consider that but honestly, I'm not sure I want to get into that much headwork. However, I will definitely think about it because it WOULD be cool as hell. I will either do the headwork with my friend, or take it to Clay Smith in Ruston. Although I am a big fan of doing stuff myself!
I'm definitely gonna find a T5, and a new head for it. Patience will pay off eventually...

Just got my CI headers on today, they look AWESOME!! Can't WAIT to get my new water pump in so I can fire it up and hear the new sound

 

[MPGmustang]

IDK but asking...

have you thought of 2x2bbl direct mounted onto the head, instead of 2x1bbls or 3x1bbls? then put a plate down the center to separate the log front and back, with some connection to equalize vacuum signal. if I thought of this before my 2bbl head conversion I would have tried it.

if you get 2 adaptors form CI and get them ready to go on I'm sure that a simply fabricating some linkage to drive both off one would be easy. and as far as I know no one else has done it yet... I think some one on the forum is... practice on one head try it and then do it on the real head and swap. would be an easy 140-160hp if you got the right cam. Still recommending something in the 270/270 112* .450 range...

Edit:

I like the Offy looks but often thought two carbs would look great and perform almost as well, like the path Invectivus is on. Two progressive Webers might be good

oh, well it looks like I was beaten...

 

[schaferstephen]

Hmmmmmmm.... That IS interesting indeed!! I'm gonna look into doing that.

Where would I get said cam, I'm assuming its a custom grind? How would it perform with my C4 till I get a T5? And would it drive ok with the stock setup till I have my modified head with either the 2 or 3 carbs?

 

[FalconSedanDelivery]

The Log will only flow so much , also 2 Two barrels would be over carbed for all but the most all out race setups , and NOT a candidate for a street car with a Automatic , the Converter required would be VERY loose ,Just not practical IMHO, and for the cost , just go Aluminum at that point

 

[schaferstephen]

Hmm... Maybe I should work on getting my T5 in first...

 

[MPGmustang]

The Log will only flow so much , also 2 Two barrels would be over carbed for all but the most all out race setups , and NOT a candidate for a street car with a Automatic , the Converter required would be VERY loose ,Just not practical IMHO, and for the cost , just go Aluminum at that point

I agree and kinda disagree...

yes 2 two barrels CAN be too much carb, and CAN make the 200/250 over carbed. BUT to compensate for that you can run 2 smaller two barrel carbs, maybe a progressive like bmbm40 mentioned. and IMO the 3x1bbl can run an auto, why not a 2x2bbl

Most cases for the i6, we want as much carb as the head can handle, but if the head can flow more than the engine can handle then we want to restrict the size of carb to compensate, with this I understand that there will be an increase of power as velocity through the carb would go up. am I understanding this wrong?

 

[FalconSedanDelivery]

Its actually simple , picture a funnel , the Log head is NOT a good flowing piece , the pressure drop over 2 2barrels will be greater than with the 3 one barrels , unless they are VERY small progressive 2 barrels , and if so why bother? , with something that is proven to work( The Triple Carb deal) and most guys have a budget and would like proven results from the money spent , and believe me the converter would;d have to be around 4500 as a min for stall speed to allow twin two barrels to work well , you could get by on less , but from a dead stop it would be a real Dog , a Stick is the Street-able way to go