TFS-1 cam, GT40 heads and Speed Density

68keyblr · Sep 5, 2007

Just for the record, I thought I'd post the outcome of my build since the combo was a bit of a question mark.

I'm still running Speed Density (MAF conversion planned next weekend).

Here's my combo:

331
TFS-1 cam
GT-40 heads, ported
93 Cobra intake
9.75:1 compression
1.6 RR's
Smog pump deleted, new cats installed

When I researched this combo before building it, I found that the TFS-1 cam didn't play well with SD.

After sorting out a few normal bugs on first startup, it runs really well! Idle is a little lopey and surges a little between 800 and 1k rpm, but all things considered it pulls hard and runs much better than I thought it would with SD.

Hope this info helps some one out

86bluecobra · Sep 5, 2007

I wondered about that cam and speed density because they seem to be very pickey about which cam you run.

robertdale · Sep 5, 2007

i installed the Trick flow top end kit on my 88 and the car run horrible. It would barely run unless you were wide open. Mass Air conv. fixed the car instantly. Maybe your combo was a little closer to stock as far as the SD computer was concerned

68keyblr · Sep 5, 2007

robertdale said:
i installed the Trick flow top end kit on my 88 and the car run horrible. It would barely run unless you were wide open. Mass Air conv. fixed the car instantly. Maybe your combo was a little closer to stock as far as the SD computer was concerned

Yeah I think that's probably true. The GT-40 heads aren't as big of a change as the twisted wedge heads.

Also I should note that I'm still running the stock throttle body so I've still got a bottleneck that's keeping airflow down.

tmoss · Sep 5, 2007

hard to tell without a dyno with A/F, but the cam may have lost just enough vacuum (casues SD to run richer) to make up the added fuel requirements of the added cubes.

68keyblr · Sep 6, 2007

tmoss said:
hard to tell without a dyno with A/F, but the cam may have lost just enough vacuum (casues SD to run richer) to make up the added fuel requirements of the added cubes.

That makes alot of sense

ras50gt · Sep 6, 2007

Get some videos posted up! So what are your thoughts on the M&R block so far?

68keyblr · Sep 6, 2007

ras50gt said:
Get some videos posted up! So what are your thoughts on the M&R block so far?

I made the mistake of using copper header gaskets so I had huge exhaust leaks. Just got those switched out last night so I should be good 2 go for a video

M&R Block is looking good so far. No leaks anywhere, so I know the gasket surfaces are true. No problems whatsoever with the bottom end - no weird noises or anything like that. I'm going to do a leakdown test real soon, I'll post the results.

I noticed that they are getting $2,200 for the 331 short block now. It's not clear to me if it's the same thing I bought or if there's upgraded parts to account for the higher price.

I'll be working all weekend, so I'll post a video next week

91foxbodygt · Sep 6, 2007

what brand and size pushrods did you use?

68keyblr · Sep 6, 2007

91foxbodygt said:
what brand and size pushrods did you use?

I used stock replacement FMS pushrods. I used an adjustable length pushrod to check for proper length, and it turned out stock length was correct. I believe it's 6.272" iirc

68keyblr · Sep 6, 2007

UPDATE - fixed the exhaust leaks...stinkin' copper header gaskets! Installed a set of FelPro 1415's and they completely fixed the problem.

86bluecobra · Sep 7, 2007

Are you using Stage 8 bolts on the headers? Since I installed them I have had no issues with header gasket failures. I swear by those bolts and there locks.

68keyblr · Sep 7, 2007

86bluecobra said:
Are you using Stage 8 bolts on the headers? Since I installed them I have had no issues with header gasket failures. I swear by those bolts and there locks.

I'm using ARP header bolts. I've have very good luck with them in the past.

The problem this time is the crappy copper header gasket right out of the box....it just plain wouldn't seal. The bolts were all nice and tight.

lang williams · Sep 7, 2007

the specs on the tf cam is right at the limits of sd, and you have to drive the car some to let the computer adjust to the changes. here's a link on sd compatible cams and you can compare the cam you want to use to the compatible ones.

http://www.50tech.com/files/sd_cams_137.gif

TFS-1 cam, GT40 heads and Speed Density

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