Impala Forums banner

LT1 Performance Parts

12K views 15 replies 8 participants last post by  Grimsin 
#1 ·
Ok Guys, Im new to the site but was loking for a little help from ones that have put performance mods on there SS such as headers, cams, roller rockers, rods, etc, Im rebuilding my motor to a 355 and want to know some good choices when Im looking for cams, headers, etc? What to get and what not to get. Thanks

95 Impala SS
All stock equipment
 
#2 ·
Why the rebuild?
First you need an above average machineshop. The stuff I see come out of even reputable shops is scary.

355 will not gain you any meaningful power over a 350 HEADS are the most critical piece to the performance puzzle.
Understand aftermarket cast cranks are WEAKER than stock if a shop suggest one walk away from that shop. The stock crank is great.
For pistons I would run a flat top Mahle Powerpak and probably a 6.0" rod say a Scat capscrew style rod or if you have the little bit extra cash Compstar.
Now those parts are not cheap but they are about the minimum I would put in place of stock parts. The stock stuff is a LOT better than people want to believe and it is easy to let an ignorant shop spec everything and endup with something LESS than stock quality.

I covered a lot of other stuff already, read through and ask questions but it is easier to give you a link than retype it all.
http://www.impalaforums.com/chevy-i...880-tim-allen-says-more-power.html#post269706
 
#3 ·
Ok I didnt mean to say 350, Im sticking with the stock crank. The reason for rebuild is simply because I have 250,000+ miles on it and want to put a little more power on it. I was looking at the headers on advanced induction and saw the 190cc heads that I like. The only thing is that I dont uderstand is how to purchase them. I dont have headers on my car now so ow would i send them a core?
 
#4 ·
You're mixing two different things there, heads and headers are not at all the same thing. The heads you do have, AI ports stock heads, thats why you send cores. Headers are exhaust manifolds, you get them new or used, but not rebuilt.
 
#5 ·
Also a 350 bored .030 over for new pistons is a 355.

AI does not port the stock Caprice/Impala iron heads, they do the aluminum heads from the Camaro/Vette and they have new cores available for I think $400 or you can look around on some of the Camaro forums/ebay/craigslist and get a set of used cores.

Really though there is a LOT that needs to be done to the rest of the car before you think about the engine.
 
#6 ·
Ok thanks Dwayne and King.. I got a better idea now thanks to yall.. One more question if you dont mind giving me some feedback.. Im going with an Airflow Research 190cc heads also going to get new pistons,headers,rods, and cam.. The guy at the shop said I should go ahead and make it to a 383 sttoker with the addidional of the new heads and cam.. Do yall suggest going the383 route or should I just stick to the original crank and just add on?
 
#7 ·
Dwayne will chime in on this soon, but the summary is, stroker is a waste of money. Not that it will be a bad motor, but for the amount of money spent you can build the top end and get a lot more power. Plus, the stock bottom end as previously stated, is much stronger than people give it credit for, and much stronger than most aftermarket parts. Best bet, get ported f-body heads, a good cam, rockers, and exhaust. Also do one of the air intake mods found on the forum here since the stock setup will not flow enough air. NOT the intake manifold, the aftermarket ones are worse than stock.
 
#9 ·
Go to the link Dwayne posted, he lists what parts are good, and what parts are a waste of money. For example, afr heads are junk, get ai instead. Before buying pistons and rings, see how the ones you have are doing, I would suggest a compression test and a cylinder leak down test. That will tell you if there are any issues, don't assume that just because it has 250k miles that it is worn.
 
#10 ·
A stroker is a lot of additional cost for relatively little gain, HP is about heads and cam far more than the bore and stroke under it.

AFR is marketing hype and magazine ads. Go look around for fast Impalas and you will find some with them BUT they will have spent a LOT more to run a given ET than the guys running similar times.

If a shop told me I needed a 383 and AFRs I would never trust them with any work. They probably don't know how to make power just how to open a catalog.

With a stock shortblock in good condition you can about DOUBLE stock HP with boltons plus good head porting and cam. Boltons can take the stock 220rwhp up to around 300rwhp and good ported heads and cam can push that up over 400rwhp some up in the 420s even and run times at the track that make the dyno look like it was reading low.

If you want to trust that shop, go for it, but you will spend more and get less than listening to someone who actually has a fast b-body.
 
#11 ·
I have two pair of F-body Aluminum Heads in my workshop. Both sets are casting #'s xxx643. I would go with an AI heads and cam 350 long before an after headed 383. Bang for the buck. I plan on doing an AI cam only setup once I have my finances in order.

I too, was once looking at doing a silly build. I think I was looking at a CC501 cammed 377(stock bore 383) with home ported heads and a stock stall. I don't know what kinda of dope I was smoking back then, but I'm glad some LT1 guys(guy, mostly... and he's in this thread) slapped me back to reality.


Either way, if you are going to do a build, you will REALLY WANT the "supporting mods". Supporting Mods, are basically the entire stock cam/heads bolt-ons list.
 
#12 ·
I like the LT4 hotcam swap from GM performance. :) It's mild enough for the street. Like everyone else, I suggest complete bolt ons, but quickly look to your suspension and other stuff. with the LT4 hot cam swap, I'd recommend 3.42 ring and pinion or 3.73.

I'm not too sure on the impala ss's rear ends but if they are the same size diff as the 93-02 f-bodies you can even pick up a WS6 Trans Am diff, they came factory 3.42 LSD, or find a formula, like mine, with the 3.42 LSD. Don't quote me on that however.
 
#13 ·
Just an FYI a F-Body rear end is not swappable into a B-Body. If I remember right the F-Body uses a weaker 7.5 Inch VS the B-Body with a 8.5 Inch rear end.
If you plan on doing an upgrade to your rear end plan on spending $1000 to $1200.. For a Gear, Differential, Barrings and labor. Also and take it to a place that does it all the time. You don't want a howling wolf under your ride..

What gear you go with is dictated by what you want to do with your Impala SS, Street, Auto Cross, or Drag race. 3:42, 3:73, 4:11 or 4:56..

Make a Choice and set your plan together.. Good Luck..
 
#14 ·
If one actually stops to consider the LT4 springs being marginal for the heavier LT1 valves that kit is far less of a "deal", then there is the fact the springs will not reliably fit the b-body iron heads.

Then the rockers will not grow with you because they are limited to about .575 lift because GM had Crane shorten the slot. In the 15+years since those parts came out springs have gotten a lot better and running cams over .575 on the street is downright common.

Plus the HOT compromises lowend more than you probably want with a much heavier b-body.

The stock LT1 b-bodies got a 8.5" axle not the fragile POS 7.5" the f-body got and the suspension is VERY different so they are not interchangable anyway, plus the Impala got a posi standard as well, and I am rather sure stock b-body tires are taller than stock f-body tires which affect gearing preferences as well, not to mention the weight thing again.

When I put 20k+miles a year on my car I like the 3.42s but pretty much all the b-body guys agree 3.73s are a good all round gear. The reason I liked the 3.42s when I put a LOT of miles on the car was the slower engine speed was just a little quieter and more comfortable, gearing does NOT impact mileage the way most people believe. They see they get bad mileage at higher speeds and mistake that for an rpm issue when it is a aerodynamic issue.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top