papas87

Hi,

So I want a nice street setup. I'm thinking some AFR 180s, a mild cam like the popular Crane 2030, and of course all the usual TBI mods. Oh, and I already have a good headers-to-tail exaust, aluminum radiator w/dual electric fans, and my vehicle is a 5.7L TBI pickup.

Assuming you think this is a good course of action, would you choose 74cc or 68cc cumbustion chamber size. Also, how much valve lift?

thanks, Jason G in Amarillo, Tx

steve8586iroc

Your stock heads have 64cc chambers so I would not go any bigger or you'll lose compression. As far as lift goes, don't go higher that the best flow area the heads are designed for. If the best numbers are say in the .550" area, you'll lose power if you run a higher lift cam than the heads are capable of flowing.
Something like that.

Steve

nidyanazo

For the tbi setup go: vafpr, ultimate mods, fi spacer 3/8" tbi spacer, and open element/cai.

I thought stock l03's were 58cc not 64cc. 64cc is L/98 right?
74/68cc is way too much. Get used tpi heads and have 'em machined.

sunset92

lo3 is the 305 motor he said he had the 5.7....

nidyanazo

My bad, I missed that. Sorry

BMmonteSS

man I hate to keep bringing this up, but your going to need some custom tuning. Your ecm is what's called speed density, so anytime you drastically change the way your engine runs your going to need to tell your ecm about it or it won't be happy and you won't be happy. Check out the DIY prom board for info on doing it your self. There have been very mixed reviews of mail order chips. The guys that don't have much changed are happy, they guys with cam and head swaps aren't.

BronYrAur

iTrader: (1)

Totally agree with BMmonte.

Also, people are suggesting wayy too much to everyone to just pick up some used TPI heads. This guy is saying he wants AFRs I think he can afford a little bit better head than TPI heads. If you've got a 350 already I'd say those AFRs are a good choice, I think I'd probably go with 190s though. You can use a 68cc chamber, just use a thinner head gasket to keep compression up. Scrap the ultimate TBI mods idea too, get a Holley 670 or a 454 TBI.

I would also go with a bigger cam than the 2030, but that all comes back to chip work. You have to be able to tune this engine or you'll hate it.

ssxmac

iTrader: (1)

Not sure if i'm right about this but thought i'd mention it b/c it crossed my mind.

I thought afr's were aluminum, dont you usually want a smaller chamber size with aluminum heads? therefore anything over 64cc wouldnt be good.

Just a thought, tell me if i'm right or wrong, b/c i'd love to know too. (read = i want afr's)

-chuck

BMmonteSS

Chamber size is directly related to how much compression you'll have. Aluminum can GENERALLY tolerate .5 point more compression than steel because it transfers heat faster. You need to sit down and do the math to completely figure out exactly what compression you'll have with a certain combo of parts. You need to take into acount gasket thickness, and how far in the bore your piston sits, along with type of piston. A flat top pistoned 350 usually has around 9.5-1 with 64cc chambers but that can change any where between 9 and 10 to1 depending on the other factors.

As for feeding this engine with TBI, you'll need at least a 454 or holley TB with 90 lb/hr injectors and lots of chip tuning. With a really mild cam I would guess it would make 330-350 hp and lots of bottom end torque, but if you decide to go with 195's instead of the 180's then it would give you more midrange to top end power, so you should definatly get a bigger cam, a hot cam should put you just over 400 hp, which is a grey area for TBI, few have pushed it that far, and I wouldn't try it till you have a good handle on chip tuning.

papas87

I looked again in my AFR catalog and the price sheet lists 2 sets(straight & angled plugs) of bare 180cc heads with 63cc chambers. This price sheet is on the AFR website as well. So I'm wondering, how much would the compression change from 64cc to 63cc? Also, have you seen the general engine specs on my 5.7L, Bore & Stroke are 4.000 x 3.800 and compression ratio is 8.5:1. Can't I afford to up the compression abit, and if so how much?

thanks for all the feedback,

Jason G

BMmonteSS

I think you meant 3.48" stroke, thats what a stock 350 has. As for how much compression you can run, thats all up to what kind of gas you want to run. You can run 87 octane up to about 9-1 and 89 up to 9.50-1. 93 should be good to 10-1, but this is all dependent on your tune and the weight of your vehicle and about a dozen other factors. I can get my motor to run detonation free on 87 octane with 9.8-1 compression as long as I pull a little timing out. I don't suggest going hog wild on compression, it's not really worth a ton of power, and if you mess up and go too far you have to tear the engine down to fix it. You just need to find out what kind of pistons you have in your motor and then calculate your compression from there. Your probably going to need the 64cc heads unless you plan on a stroker or some form of forced induction.

Damon

The AFR 180 heads actually outflow the larger 195s slightly below .450 lift. Plus, of course, the better velocity of the smaller port. AFR no longer makes the 190 head- just the 195, although they were practially the same head anyway except for the size of the intake port opening.

If you don't plan on lifting the valves above .500" or spinning 6000+ RPMs then the 180s are probably a VERY good choice.

I'd stick with the 64cc chambers if that's what your original 350 heads had (most 350s built after 1987 came with 64cc heads). Compression might still be a smidge lower than you would like, but I agree with the post, above, that high compression is not the end-all be-all of making power.

papas87

Concerning the stroke of the engine, I'm only going by the "General Engine Specifications" chart in my Chilton's manual. It has it listed as 3.800 for the '87 EFI 350 as well as for both varieties of 4bbl 350s in '86. Can anyone varify if the manual has a misprint?

thanks, Jason G

BMmonteSS

yep, misprint it's 3.48 Quick and dirty rule of thumb, flat top pistons with 64cc heads make 9.5 to one. Dished with 64cc heads make 8.5 Dished with 58 cc heads make 9.5.

Avenger007

how about going with a turbo city 2" stock tbi or boring your stock unit. bore to 2" then do ultimate tbi mods and youll find good flow plus your IAC wont give you problems or any cables and hookups for that matter...for the most part

BMmonteSS

2" is 2" but most people go with the 454 TB because you get the big 90 lb/hr injectors with those, and they aren't that bad in price if you can find one in the junk yard. If you can't find one it might be cheaper and easier to get one of those TB's and just buy the 90 LB injectors.

Gunny Highway

iTrader: (1)

I have a cam and head swap on my 350 and I'm happy with my mail order chip.

And once again, I recommend against using 90# injectors. WAY too much fuel. . . 65#ers do the job. Hell, I have 55# running at 20psi, and I'm rich.

BMmonteSS

ummm, your 65's are acting like 90's. I guess how well a vehicle runs is in the eye of the beholder.