My poor car's been sitting for a few years now since I did the LT1 intake swap and haven't spent the time to tune it right. With another kid on the way I don't see my weekends opening up so rather than letting it rot I think I'm going to put a carb back on it so I can actually drive it.

The engine is a 355 L98 with LT4 hot cam, 200cc Pro Topline iron heads, ~9.5:1CR, shorty Hooker headers. Trans is T56 and rear is 3.42. I don't race at all, the car will see only street duty.

First question, is the cam and 200cc heads a total mismatch? I'm thinking maybe I should have gotten the 180's way back when but the shop I got them from was used to building sprint cars so they thought I should go bigger. The cam is 218/228 duration @.050" lift, .525"/.525" lift with 1.6 rockers.

Next, what should I do for a carb and intake? I'm thinking a dual plane intake and mechanical secondary carb in the 650-700cfm range? Any particular models I should look at?

 

I've heard great things about the Edelbrock air gap manifold, that's what I'm buying to replace the torker 2 on mine.

 

Any Edelbrock RPM intake should be fine. Dual plane and flows well... up to 6k RPMs.

The RPM Air Gap has the same runners so it flows the same, it just has a raised runner design that isolates the runners from the engine a little more. In theory it keeps the intake air cooler for more power, but I think all it does is make the car run crappier when its cold. That intake will completely warm up to engine temp, it will just take a little longer. In the meantime you'll be tuning the car to run well at operating temperature, not when it's cold - so it just makes the car run worse for longer. Just a gimmick to me.

But it's popular, and it flows fine so that once the car is warm it will work just as well as a regular Performer RPM intake. It wont hurt your peak power numbers.

I say just go with the cheapest RPM intake you can find used, whether it be air gap or just a regular performer RPM.

I dont know so much about the Weiand intakes, but I do know that the old Holley Street Dominator intakes were good, but they dont make them anymore.

The hotcam isnt awesome, its actually kind of outdated. But I've seen Vortec-headed cars do amazing times with those. It's still a decent roller cam and will make good power. As far as it matching with the heads, I honestly dont know enough to really say. I would imagine it'll make great power anyway. Will it make more torque with the 180cc ports? I dunno, maybe, but you've already got em so I'd just run em and see what happens. Keep it simple.

The carb... I think we all know teh only real answer to that - Holley 650/750 DP. The 650 might be slightly on the small side, but theoretically it is plenty. Theoretically doesn't count for much in reality, though. There's a lot of voodoo in those cfm ratings and a lot of guys advocate running the biggest carb you can afford to begin with. I figure a 650 will work fine and so will a 750. Just get whichever you can find the easiest.

 

to reply on the carb section i would definitly go w/ a holley. there are way more parts availble for tuning and rebuilding than other companys. a 650 cfm is gonna give you better throttle response, a 750 you'll get more horepower at top end. w/ a 5-spd you need a mech secondary carb. I llike the new holley ultra d- pump w/ electric choke. thats what I'm running now, no problems at all. its all aluminum lite weight. ready to go out of the box.

 

Also I would recommend a edlbrock rpm intake its good for street manners. you should consider upgrading your dist- setup too. a nite and day differnce w/ a new carb, intake and dist! just did this myself a few months ago.

 

The dual plane intake is ok but if you want to make power you def want a single plane the weiand team g intake still works good at a lower rpm but is still good up top and the only way to go is with a pro systems cab their custom made to your motor but mine was cheaper the the ultra hp from summit and is still a holley 4150 base

 

Can you further define 'make power'? cause I've seen cars make over 650HP naturally aspirated with Performer RPM intakes.

Also I'd say a Pro-Systems carb for a regular ol' mild street car would be a very very poor investment. There is really no need for a "fancy" carb on such an application... in my opinion anyway.

 

Are you guys familiar with this intake at all? This is what I have right now. I'm not sure if it's "good" but I think it'll probably do the trick with the right carb. It's stamped Dart but from what I can find it's something they made for World Products.

 

back in the day Dart used to have some sort of relationship with World. That intake is technically a World but cast by Dart (I think). It's not a bad intake from the ones I've seen. They're more or less "as good" as an Edelbrock RPM.

Your current combo is otherwise just fine. Is it optimal? Probably not but you're just building a driver so I wouldn't worry about changing stuff.

 

Spoken like someone who knows just enough to get in trouble.

Im going to second what the other guys said and say "pffft".

If you want to spin it to 6500 and beyond, then sure, go with a single-plane intake. If you want a car thats streetable and you didnt put a $2000 bottom end in it, then just go with the dual-plane.

 

I found a Holley Street Avenger 670cfm on craigslist, I might try to pick it up. I thought I'd end up with mechanical secondaries because of the manual trans but this one has vacuum secondaries. I looked up some Holley tech docs and they only recommend mechanical for all out race cars that are lightweight and have low gearing.

 

The Dart intakes are great and perform the same as the equivalent Edelbrock RPM intakes.

 

They only recommend mechanical secondary carbs to as few people as possible because too many people dont know how to tune them to work on any given vehicle.

Vacuum secondaries are for lazy people and grocery wagons. There's a reason that NO ONE so far has recommended a vac secondary carb to you - you have a manual transmission. Can you make a vac secondary carb work? Sort of. But mechanical secondaries are gonig to be much better for your combo. If you had an automatic I'd still recommend mechanical secondaries, if you had the patience to tune it properly.