redman76

I'm finally ready to start attacking my L48 engine and need some help with getting the right combination of parts to meet my goals. Here is what I have now:

- 350ci 2-bolt mains
- Edelbrock Performer 2101 Intake
- Hooker Sidemount headers and side tubes
- STS Baffles
- HEI upgraded with Petronix FlameThrower and shimmed shaft to correct end-play
- AC
- TH350 with Transgo shift kit
- 3.08 rear gears
- Stock Q-Jet

My long-term goal is to build a 383 with forged crank, rod, pistons -- probably in a new GMPP 4-bolt main block with a target of 425-450 HP at the crank. I don't have the money to do the bottom end yet, so I'm only wanting to focus on the top end right now. I know it is risky replacing top-end while not rebuilding bottom end, but it's just not in the budget right now. I'll do a compression check before I start to make sure there are no obvious issues and will be happy to get about 350 HP at the crank for now with this upgrade.

I would like to buy parts now that I can reuse with the future bottom-end rebuild. I'm also planning to install 3.73 gears, AT tranny with overdrive, and higher stall converter, but these will be subsequent upgrades as well. This car is a weekend toy when it's not apart. It may see some 1/4 mile and autocross track time, but just for some occasional fun and looking/sounding cool for the cruise-ins. Also, I don't mind if it sounds "lopey", in fact I would prefer.

My budget here is $1500. I've looked at the Vortec head swap, but it starts adding up fast when I have to replace intake and valve covers, so it is not looking like the best bang for the buck in my cost analysis. The new Edelbrock E-Street heads look promising and fit the budget. I've read here on CF that the Brodix IK180s would work good; they have good flow numbers and are within budget or pretty close. I know the cam that I'll be selecting will be replaced when I do the bottom-end, so my thought was to buy one of the Summit 1103 cams that I can toss later on, but please -- I'm open to anything at this point; this is where all my research has led me thus far. I'm planning to buy heads, head gasket, ARP bolt set, stamped steel rockers, pushrods, lifters, cam, timing chain & gears, and whatever else I need. I'll replace the intake when I'm ready to do the bottom-end too.

Having said all that, what heads give me the best migration to my future power goals and what cam is going to make me smile now while not blowing out the bottom-end. Sorry for the long post, but I wanted to give as much info on the frontend as possible.

What are your recommendations? . . . .

billla

Sounds like you've got a realistic perspective on what you want to achieve - and the risks of topping a tired shortblock.

IMHO, there isn't an easy way to reuse parts from a low compression, low RPM 350CID top to a 450HP 383CID build and maximize the potential of both builds. They're just two completely different animals. Others will certainly disagree, and they may well be right

Any suggestions I make are based on the top for your L-48, not for any future reuse There's a thread addressing a virtually identical configuration, and I don't know that my recommendations would be any different for you. Either head choice is a good one.

http://forums.corvetteforum.com/c3-t...er-intake.html

redman76

I've been following along the other post; I'll go back through it and post any questions I have here. I'm not necessarily trying to optimize my current build, but don't want to shoot myself in the foot either. Worse case, I guess I can sell the heads once I get ready to build a 383.

I'm open to ANY recommendations at this point and may be able to stretch the budget to $2K if necessary. With the extra $500, would I be able to freshen the bottom-end with some flat-tops?

Little Mouse

Most of what kills bottom lower end torque is high duration cams the cam is a far worse culprit then larger runner heads stick your money in the heads you want for the 383 build, a little larger runner then just use a milder cam suited for your 350. buying reselling heads is just not worth it.

redman76

Are the 180s too small for a 383 with my HP target? I like the idea of camming down for a 350 for now. Other than cost and overkill on flow, what are the downsides to running larger heads than you need on a 350?

V8 Stingray

Hi Redman,

Have the same dilema in the parallel thread that Billa mentioned.... My config looks near identical to yours other than I dont have an upgraded ignition system.

I wont be looking to do the bottom end - so putting too much stress on the stock bottom end has been a concern for me too. I started with the same budget, but that soon changed... If I were to stick my greedy hat on to try and get to where I want to go, I would need a roller cam and probably end up with a broken motor - but you are then into a budget that is similiar to a new crate! I've posted in my other thread a summary of costs thus far.... I've added in a holley carb on top of that as well, but if you take that out - it's bang on $1500 (excl shipping etc).

Good luck with the build! Either way, you are in the right place for some excellent advice

vettesbydesign

Before both you guys purchase.....pm me your wants w/part numbers,and will beat any price that you can get from anywhere else.
These will be in stock,and ship the same day as payment received.
I'm not a engine builder like these guys.I do body work,and parts,but I run the IK180s w/some massaging,and they made a WORLD of difference over some tricked out 65 fuelie heads that were on the car.

redman76

I'm interested in hearing more about running 383 sized heads on a 350 if anyone has some input. I'm more interested in leveraging my investment down the road than optimizing for performance now. Thanks for all the great input thus far.

Thanks for dropping in . . . I've been following your post with great interest. Funny you mentioned the crate engines -- I was looking at that option again yesterday. I think for right now though, I'm going to stay with just doing the top-end. Trying to make some bigger HP is tempting and a great way to break things. Sounds like we are trying to walk the same tight rope. I just want to get my car back on the road and get rid of those smog head once and for all.

And you're right, lot's of great help here on CF. I've learned sooooo much in the last four years here that I don't know what I would have done with my car if I never stopped in. Thanks for supporting my addiction.


Everything I've read and heard about the Brodix IK heads has been good. I'm leaning that direction right now unless someone convinces me otherwise. I'll shoot you a PM when I get a little closer to pulling the trigger.

billla

All IMHO : A 180cc head is fine for a warm 383 making around 1 HP/CID, and for a warm 350 making up to about 1.1 HP/CID. Once we start talking about a 1.2 HP/CID 383, a 195cc or better is needed. I guess the middle ground would be to pump up your 350 build with too-big heads and cam to match...and figure you're going to break it or to build a fairly mild 383 that may not make big HP numbers...but would still be a torque monster. With your gear change, option 2 wouldn't be a particularly good pick as your RPM range is going to change a bunch.

You can run big-port heads with a mild cam...but the intake velocity ends up being poor and this is reflected in poor off-idle and low-speed driveability; you end up pushing through 3500 RPM to get some grunt, and wrapping it to 5500+. This is not the approach for longevity in a very old bottom end.

No easy answers...

Little Mouse

I can tell you have made up your mind on the IK180.

Why did you pick a header with 1 7/8 primary tubes huge 4 dia collectors let me guess they do look good.

redman76

Is it me or did Little Mouse's post with the Lunati cam recommendation disappear?

So for this upgrade, long duration is bad and lift is good for TQ? What about using higher ratio rockers? Would that help?

Billa, what you say makes a lot of since. If we can find a way to midigate that off-idle lag though, even if it's not ideal, I'll hopefully be in a better place. But your right, I don't want to build something that's going to drive me crazy everytime I get behind the wheel . . . that's what I have now.

Little Mouse

I deleted the post fiqured you had made up your mind on the heads.

You want all the lift you can use, lift is always your friend and the quicker the lift rate the better for torque.

The 60101K lunati cam kit would make a good match duration wise
with your 3.08, 3 speed auto tans. Its a more modern quicker lift
short advertised duration cam but it costs more money then the summit stuff. $194.00 cam lifters the summit stuff is around $85/90.

If I were doing it I would pick up eight 1.6 rockers for the intake valves but this will for sure cost you some extra for different length pushrods, you can buy a full set of hardened push rods for the guide plates that come on the brodix head for around $40.00 that will more then do the job for hydraulic flat tappit valve springs you won't need any fancy $80.00, .080 wall chrome moly pushrods for what your doing.

even with your dished piston your going to pick up some more torque from the 64cc chamber new heads over your 76cc factory heads regardless of the runner size your going to pick up airflow everywhere over the poor factory stuff the 60101 cam also has a 112 LSA for good idle vacuum or off idle performance. The IK180 at $1055.00 is very tempting when you start looking at heads like the AFR180 at $1510.00 1/3 higher price tag.

you really would be better off with a bigger head for a 383 as long as you don't get silly in duration size with your gearing you could use the bigger runner heads you would mostly just not be using them to there full benefit without more cubes and more cam that you could run in a 383.

redman76

OK, I guess you withdrew your last post. I haven't made up my mind on the IK180 . . . the IK200 are the same price. What would you recommend? I'm open to any input I can get. I'm a rookie at this stuff, just having fun and learning as I go. I'm very dependant on the info that I get here. You guys have done this a lot more than I. I just want to make as informed a decision as I can. Right or wrong, I'll still be in a better place than if I was trying to do on my own.

And yes, I picked them because they look cool. How did you know?

redman76

That is still a reasonable expense to me . . . I have some room in the budget.

Little Mouse

I doubt you could use the IK200 with a performer manifold it has a very big 1206 fel pro gasket opening, interesting that brodix came out with an IK210 last couple yrs that went back to a smaller opening 1205 gasket other 195 to 200 brand heads tend to use the 1205 size.

Little Mouse

About everyone like's the way they look but they are what they are
with big primary tubes big diamter collectors are all high rpm stuff
where a side exhaust road raced car would be at all the time compaired to pulling up to stop lights taking off, but they did not really ruin you when you put them on your car some things can get a little overblown.

redman76

I noticed they have 2 models of IK200s -- 1021000 & 1021001. On Summit's web site, there was a note on the 1021001 head that "The larger intake ports on these heads will not accommodate stock or low rise style intakes. Please see the Recommend Parts tab for compatible intake manifolds." But I'll verify before I buy anything . . . thanks for the heads-up.

Do you know a head that you feel would better meet my goals?

Little Mouse

Dart recently revamped there heads. the etec 200 edelbrock uses a raised .200 intake runner would make you have to buy a new manifold,
look at afr, dart, trick flow. some of the other stuff from china could be a gamble on quality

I don't think if you start looking at 195 to 200 heads there is much of a price difference in a set of afr heads like there is between brodix 180.

Be carefull on the 195 200 heads as to what springs they come with
you don't want to stiff a spring for a flat tappit cam, hydraulic roller springs are stiffer then flat tappit springs.

If you change your mind back to the 180 brodix the BRO-1021004
has 64cc chambers with standard diameter 1.250 springs that handle up to .520 lift.

Little Mouse

OK i looked up the two brodix heads, the BRO-1021000 has 1.250
.525 lift springs. the BRO-1021001 uses 4.300 dia springs .575 lift.
both heads are strait plug.

The 1.250 .525 lift springs are the factory dia would most like be spring pressure and lift for hydrauilc flat tappit cam.

the .430 .575 lift springs are most likely the right springs for a hydraulic roller cam.

Man at $1055.00 for the IK200 this is a very tempting head at this price you could even afford to change to a better high rise manifold, your 76 has room under the hood for one with a drop base. The rpm edelbrock can be used with the bigger 1206 gasket.

Little Mouse

Brodix IK200 part # BRO-1021000 = $1055.95
Edelbrock RPM Q-jet part # EDL- 7104 = $167.95
Lunati cam lifters Part # 60101K = $194.00