head and cam swap

[nosfed80]

hi guys,im the new,proud owner of an 80 white targa corvette.l82 engine.i love this car(80-82 bodystyle is the most beautifull,for me,however) but it lacks performance.my goal is to be able to keep up with my buddies 99 ls1 z28(about 270rwhp).Only things done are 600cfm carter carb,dual exhaust,new tranny with shift kit.idont want to go the nitrous route.what cam sould i use.how much duration at 0.5lift is still steetable with the stock converter?should i only swap heads and bolt on headers?what the performance diff with or without headers?I think heads only would make a big difference in compression and flow.what heads would you guys reccomend with stock pistons?i know thats alot of questions,but i need those answers!!thx guys.

 

[Copdogcorvettes]

My first thought would be to install a TPI unit on and throw the carb away. Not that I think carbs are bad, but the TPI works SOOOOO much better. Better gas mileage and more horses all in one. Beside it looks better. A mild cam with better heads will always help. With an auto trans you can't good to high on the left & duration.


Good luck on what ever you do.

Gary

 

[nosfed80]

I had an 350tpi gta.too much low end tq for the street and runs out of breath at4500rpm.I want to stay carb cus theres nothing like the sound of a 4barrel at WOT.

 

[80vette_ca]

I thru headers on last summer and noticed a big difference in performance, the only thing that bothered me was that the car got quieter at idle, but at WOT it sounds just great, As far a 1/4 mile times I went from 16.3 down to 15.6 with the flowtech headers, new spark plugs and plug wires so it was a great improvement, This was all measured on my G Tech Pro, and I am not nearly the best driver so I wasn't able to get a good launch. I am running an auto as well w/ 2 1/2" pipe running back to some super turbo mufflers, no cat and a 620 cfm carter carb and the edelbrock intake, as well as some other internals done. If i were you i would definitely go with headers and throw on some aluminium heads if you can spare the cash, as far as the cam goes you'll have to get someone a little more knowledgeable on that one.

 

[Copdogcorvettes]

Well then, still mild cam, performer intake, 650-750cfm carb and Hooker headers & Side pipes. Heads: 202 valves ported & polished with about 68cc chambers. compression ratio, depending on the gas you can get or afford to buy i would say to stay around 9:1. 9.5:1 at the highest. As to acam I was just thinking; maybe look at one of the older 327-350hp cams. Nice street cam and you can say it is chevy stock cam.

Now the other thing to think about is Turbo charging or a 144 street charger. Both will make great power for the street. If you go this way compression should be under 8.5:1.

These are just a few idea to think about.

 

[nosfed80]

turbocharging with carb?are there some kits out there?CR is 8.5:1.Iwould be veeery interested in an 144 charger,but i dont know if this thing will EVER fit under the stock hood.then again,i saw an centrifugal supercharger for carb applications in the summit catalog.Is it easy to get a good tune if you put an supercharger on an carbed engine?What do you guys think of those vortech centrifugals for carbed cars?

 

[nosfed80]

80vette ca i dont want to offend you or other guys,but a 15.5 e.t. sounds very slow to me.my 80 can hang with an 330hp(flywheel)audi s4biturbo from a roll.from a dig never,but from a roll i hang with him till 120mph.

 

[Copdogcorvettes]

Check out B&M or Holley for the street chargers. You can look at Jegs also. I have seen complete units both Street Chargers and Turbos on E bay. As to fitting under the hood you have to go to an LT-1 style or something like that to fit it all in. I really don't like the Paxton type unit for use with a carb becuase of all the sealing on the carbs to hold the boost in. When I was racing in the 70's with the Ford 2000cc motors I used a turbo. I was run around 200HP and it was streetable. At the Portland Int. road track we turned 162MPH down the straight with the motor in a 71 Pinto. Not to bad for Pinto. I do have to say there was a lot of other things done to the motor to make it work with the turbo. Also turbo can be a Pain In the A## to install with the exhuast and oil lines.

Hope this helps in some way. At least it give you some things to think about.

Gary

 

[Robin7TFour]

NOSFED, a cam will help, use caution in selecting if you're going to keep the stock converter. the previous owner of my car put a healthy street cam.it runs strong in the mid range,however,idle is a real PITA. i need to eventually go to a converter that will add 500 rpms of stall.
just wanted to let you know,,

ROBIN

 

[MaineShark]

80vette ca i dont want to offend you or other guys,but a 15.5 e.t. sounds very slow to me.my 80 can hang with an 330hp(flywheel)audi s4biturbo from a roll.from a dig never,but from a roll i hang with him till 120mph.

15.5 is better than stock: see here

If your car can do better than stock, someone may have already made some performance enhancements. You may want to check casting numbers on your block and heads to make sure whether or not they are original, since any recommendations made here might have to be changed if your engine is not stock (eg, a different compression ratio).

Joe

 

[Glensgages]

i dont want to offend you or other guys,but a 15.5 e.t. sounds very slow to me.

I don't know what doesn't 'sound-slow' to you, but a 327/350 cam, L-82 intake & re-worked Q-Jet, and 64cc heads with 1.940"/1.500" valves, and headers on top of a stock LM-1 in an '80 Z28, stock converter & THM350, 3.42:1 gears & 225/70R15 UNIROYALS, went 14.60s @ 95 MPH thru the exhaust;
My '79 Z28, built similarly ('65 Vette intake, 650 dbl-pump Holley), with a shift-kit and open-headers, ran 14.40s @ 97; with 4.10 gears, 14-teens @ 98.

I'd think a pair of Edelbrock heads, good dual-plane intake, 650 carb, .460" lift/224* @ .050" lift cam, open headers, 3.55/3,73 gears, and maybe a looser converter, would run EASY 13-second ETs @ close to 100+ MPH...

and your C3 looks a Helluva lot better than a 330hp Nazi-nut-mobile, too!!!

 

[nosfed80]

and your C3 looks a Helluva lot better than a 330hp Nazi-nut-mobile, too!!!

you are sooo damn right!!audis suck big time

copdogcorvette,what do you think,how much time does it take to install a centrifugal type supercharger on a carbed application?Is it worth the hassle or should i swap head and cam?for the street and with the stock CR a supercharger seems to be the way to go.

 

[Copdogcorvettes]

If you are pretty good with the wrenches you got install one of the street blowers in a weekend with a little luck. If you go this way I'd with electric fans for the radiator as well, just for the extra room.

Like I have said that is just one way to go. The heads, cam, intake& carb and header is the most common way to biuld up the motor. These are very good things to do even if you want to put the blower on. If the money is there; decide what you want to end up with as far as compression ratio. Then start doing all things to get to the desired end.

I my mind I would start with the cam, heads, headers and intake. Then if you want the blower add that. The work you do first will make the whole package come together at the end. If you are going to stay with the lower compression for a blower; then you may not need to do change your heads to start with. Bigger valves and a port & polish never hurt. Also if you are going with the blower make sure the cam is right for that; ask one of the cam companies and tell them you are adding the street blower. It makes a difference when you are blowing air in under pressure not pulling it in with vacuum.

One of the small street blower like the 144 and the 170s are an easy way to get Hp with out a lot of changes to the inside. Just look at the new car that are out now many of the 4cyl and v6s have some sort of small blower on them.

The choise is yours, you bolt on the one of these blower and not do much else to the motor and gain a lot. Then if you add matched other changes you can gain even more and add to the driveablity and realiablity of the whole package.

Gary

 

[80vette_ca]

80vette ca i dont want to offend you or other guys,but a 15.5 e.t. sounds very slow to me.my 80 can hang with an 330hp(flywheel)audi s4biturbo from a roll.from a dig never,but from a roll i hang with him till 120mph.

I'm just giving you an idea of how much of a difference that can make I never mentioned that is the best i have done as more has been done to the car since but after the headers and a quick tune up to shave off that kind of time in the 1/4 mile doesn't sound very slow to me, but then agan what do i know anyways? I do agree though that a supecharger or turbo would be oh so sweet if you can afford the price.

 

[nosfed80]

80vette ca.sorry,i just realized what you wanted to say,youve cut a whole second of your 1/4 with just headers.thats great!!.I didnt say my c3 is faster or so,mine absolutely sucks of the line..but once it reaches 3k rpm it pulls pretty hard.but generally,those c3 lack power.i just want to hang with my ls1 buddie.to be exact,i want to BLOW HIS DOORS OF.the more i think about it,the more i want the centrifugal SC.roots type would be sooo cool,but hood clearance?

 

[AKRAY4PLAY]

80vette ca.sorry,i just realized what you wanted to say,youve cut a whole second of your 1/4 with just headers.thats great!!.I didnt say my c3 is faster or so,mine absolutely sucks of the line..but once it reaches 3k rpm it pulls pretty hard.but generally,those c3 lack power.i just want to hang with my ls1 buddie.to be exact,i want to BLOW HIS DOORS OF.the more i think about it,the more i want the centrifugal SC.roots type would be sooo cool,but hood clearance?

if you blow it, you'll have to loose the hood. forced induction has benfits and compromizes. a turbo is slow out of the hole, lag time to wind up. a super charger is big and has more moving parts. new heads, cam and exhaust will make your car faster than an LS1 and at a lower price than forced induction. NO MATTER WHAT ROUTE YOU CHOOSE, MAKE SURE THE BOTTOM END CAN HOLD IT! it would be a crying shame to build up a fun car and have the bottom blow out and leave you without a workable block.

what is your budget and power goals?? these two questions will greatly reduce the number of suitable paths to reach your goal. off the line performance is better with pure motor or supercharged, not with a turbo. oh ya, what are your emmissions laws like?? Brian

 

[nosfed80]

emissions are no problem,but here its not allowed for a scoop/air cleaner to stick out of the hood...so you say if i swap heads and cam i will be faster than an stock ls1.my buddies ls1 dynoed 360flywheel hp.In summit there is a trickflow head/cam package,they claim it should make 420hp/400tq on a 350sbc..how are those summit numbers meant?for sure not rwhp.but is it net hp or gross hp?that would be a big difference..if that one makes 420hp at the flywheel,i have to order it asap.i looked alittle on ebay and saw numerous 383 and 350 engines(new or rebuilt with quality parts)making 400+hp.they sell for 3500dollars.that sounds veeery cheapo to me.whats the deal with those engines on ebay?there is a 454BBC making 500hp for 4000dollars?!?

 

[AKRAY4PLAY]

if you like durability, stay away from the Trickflow heads. they are prone to cracking from the thin castings. they are a decent head for the buck, but for a couple hundred more i would splurge and get the AFR 180's or 190's for a 350ci. AFR's out flow the other heads, and porting them results in major flow. they are just a great head at an affordable price, $1150 a pair. a long rod 350 with ported AFR 180's and a good cam with 10.3 compression ratio should net you 450 hp at the crank and around 420-425 ft/lbs. rods are $400, pistons $250-$450, machine work $800, cam $200, retro roller kit $200 and gasket/misc $300. so if you do the labor part, you can have a solid screamer for about $3500. i like doing my own work, never been able to trust someone's word when it comes to a huge chunk of my money possibly going in the trash can. you'll want headers and 2.5 inch duals to make any motor breath better!

buyer beware with motors on Ebay. there are some guys that build good motors and sell them over Ebay, but there are more of the shady types that want the money and run. it is real easy to get another Ebay account after shanking someone.

i can send you a build sheet of my 406, it is spendy and overbuilt but it makes 606hp and 588ft/lbs normalyy aspirated on pump gas. probably overkill for the prices you pay for petrol. Brian

 

[nosfed80]

its not the cost of the afrs wich is a problem,its the delivery time of min. 2-3months.I have to say your engine rules.600hp out fo 406cui on pump gas is a thing to consider..send me your build sheet if posssible,im very interested.i wonder what that costs,too.So you say changing the pistons(on my 350)would be good too.in terms of what?Compression ratio only?BTW if i can get 400+hp out of my 350 with other heads then afrs,i dont even consider using those afrs.

 

[AKRAY4PLAY]

sorry for the delay, i was out on a 3 day rig job.

you can get 400hp out of your 350 without AFR's, but it is easier to make hp with better flowing heads, so AFR's cost a little more up front but save you in less expensive "power parts" later. Dart Pro's and Brodix are other good heads that will get you there as well. as for your bottom end, i would run 6.0" rods and flat top pistons at zero deck. keep your compression around 10.3-10.5:1 and a healthy cam. you will reach your goal for a pretty low cost in comparison. i will email you a built list for my 406 as well as a dyno sheet. you may want to talk with this guy, http://www.cfmperformance.com/. his name is Mike Stark, and he was very helpful in selecting and purchasing my parts. he had AFR's in stock and the lowest prices i could find. Mike does not push commissions, he sells what works. everything is tested by him on his own flowbench, so the numbers are real. i trust Mike fully, he took several days of his time to explain different options when i was in the planning stages of my 406. if anything, it will be another opinion to considder. i will send you those emails later tonight, got to get back to work. Brian